ci: retrigger test after cancelled lint-and-test again (#4142)

Fixes #4136.

When the terminal utilityProcess console pipe is already dead, classifyProcessError marks EPIPE / ERR_STREAM_DESTROYED as ignore, but installTerminalWorkerErrorGuards still called logError → console.error. That write failed with EPIPE, re-entered uncaughtException, and busy-looped.

- On action === ignore: only report, never logError.
- Latch consoleBroken on stdout/stderr error so the default console.error path no-ops after the transport dies.
- Harden compressed extract cancel rollback under SIGTERM (ignore HUP/INT/TERM during cleanup, unlink archive first) and stabilize the FIFO cancel test that was flaking CI.

Out of scope: #4128 main-process EIO twin.

.gitignore

@@ -170,3 +170,6 @@ build_with_vs2022.bat
 /resources/et/*/et.exe
 /resources/et/*/et-*-dlls/
 /resources/et/*/*.dll
+
+# Local plugin example staging and bundles
+/examples/plugins/*/.package/

AGENTS.md

@@ -127,6 +127,11 @@ second private RPC shape when extending the host.
 - `PluginRpcRouter` owns correlation, cancellation, deadlines, stream credit and
   protocol-failure containment. Runtime identity is assigned by the host and is
   never accepted from request parameters.
+- Custom views use only host-rendered DOM: plugin scripts stay in the isolated
+  runtime; the host validates incoming trees, styles, resources and events before
+  rendering. Never reintroduce native child views, iframe UI, or plugin code in
+  the host renderer. See `docs/plugin-platform/host-rendered-ui.md` for authoring,
+  lifecycle, limits and verification.
 - App quit goes through `runPluginShutdown()` after the dirty-editor guard; do
   not add another independent quit interception path.
 

App.tsx

@@ -50,6 +50,9 @@ function SettingsI18nProvider({ children }: { children: React.ReactNode }) {
  * shell bags; AppSideEffects owns reactive effects + local UI publishing.
  */
 function App() {
+  useEffect(() => {
+    performance.mark('netcatty:renderer:app-mounted');
+  }, []);
   return (
     <AppLocalStateProvider>
       <MonitorRuntimeHost />

application/app/AppHandlers.createLocalTerminal.test.ts

@@ -0,0 +1,84 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { handleCreateLocalTerminalImpl } from './AppHandlers';
+
+type CreatedLocal = {
+  shell?: string;
+  shellArgs?: string[];
+  shellName?: string;
+  shellIcon?: string;
+  localStartDir?: string;
+  shellType?: string;
+};
+
+function createCtx(overrides?: {
+  localShell?: string;
+  localShellArgs?: string[];
+  discoveredShells?: Array<{ id: string; name: string; command: string; args?: string[]; icon?: string }>;
+}) {
+  const created: CreatedLocal[] = [];
+  const logs: Array<{ hostLabel: string }> = [];
+  const localShell = overrides?.localShell ?? '';
+  const localShellArgs = overrides?.localShellArgs ?? [];
+  const discoveredShells = overrides?.discoveredShells ?? [];
+  const getCtx = () => ({
+    addConnectionLog: (entry: { hostLabel: string }) => {
+      logs.push(entry);
+    },
+    classifyLocalShellType: () => 'unknown',
+    createLocalTerminal: (options: CreatedLocal) => {
+      created.push(options);
+      return 'session-1';
+    },
+    discoveredShells,
+    resolveShellSetting: (
+      value: string,
+      shells: Array<{ id: string; command: string; args?: string[] }>,
+      customArgs?: string[],
+    ) => {
+      if (!value) return null;
+      const match = shells.find((shell) => shell.id === value);
+      if (match) {
+        return { command: match.command, args: customArgs?.length ? customArgs : match.args };
+      }
+      return { command: value, args: customArgs?.length ? customArgs : undefined };
+    },
+    systemInfoRef: { current: { username: 'qi', hostname: 'box' } },
+    terminalSettings: { localShell, localShellArgs },
+  });
+  return { getCtx, created, logs };
+}
+
+test('create local terminal resolves Settings custom absolute path when no shell arg is passed', () => {
+  const custom = String.raw`C:\Users\lybing\AppData\Local\Programs\nu\bin\nu.exe`;
+  const { getCtx, created } = createCtx({ localShell: custom });
+  handleCreateLocalTerminalImpl(getCtx as never);
+  assert.equal(created.length, 1);
+  assert.equal(created[0].shell, custom);
+});
+
+test('create local terminal ignores MouseEvent-like first args and still uses Settings shell (#4085)', () => {
+  const custom = String.raw`C:\Users\lybing\AppData\Local\Programs\nu\bin\nu.exe`;
+  const { getCtx, created } = createCtx({ localShell: custom });
+  // Vault header historically used onClick={handleCreateLocalTerminal}, so React
+  // passes the click event as the first argument.
+  const fakeClickEvent = { type: 'click', target: {}, preventDefault() {} };
+  handleCreateLocalTerminalImpl(getCtx as never, fakeClickEvent as never);
+  assert.equal(created.length, 1);
+  assert.equal(created[0].shell, custom);
+});
+
+test('create local terminal still honors an explicit shell object', () => {
+  const { getCtx, created } = createCtx({ localShell: 'pwsh' });
+  handleCreateLocalTerminalImpl(getCtx as never, {
+    command: String.raw`D:\portable\zsh\zsh.exe`,
+    args: ['-l'],
+    name: 'Portable Zsh',
+    icon: 'zsh',
+  });
+  assert.equal(created.length, 1);
+  assert.equal(created[0].shell, String.raw`D:\portable\zsh\zsh.exe`);
+  assert.deepEqual(created[0].shellArgs, ['-l']);
+  assert.equal(created[0].shellName, 'Portable Zsh');
+  assert.equal(created[0].shellIcon, 'zsh');
+});

application/app/AppHandlers.ts

@@ -16,6 +16,7 @@ import { isPortForwardingAutoReconnectEnabled } from '../../domain/portForwardin
 import { buildNumberShortcutTabTargets } from './tabShortcutTargets';
 import { captureInheritedCwd } from '../state/inheritedCwd';
 import { fromEditorTabId, isEditorTabId } from '../state/activeTabStore';
+import { isPluginViewEditingTarget } from '../state/pluginKeybindings';
 import { resolveBatchTabCloseFocus } from '../state/pluginViewTabStore';
 
 type AppContextGetter = () => Record<string, any>;
@@ -264,7 +265,7 @@ export function handleGlobalHotkeyKeyDownImpl(getCtx: AppContextGetter, e: Keybo
       }
     }
 
-    const isFormElement = target.tagName === 'INPUT' || target.tagName === 'TEXTAREA' || target.isContentEditable;
+    const isFormElement = target.tagName === 'INPUT' || target.tagName === 'TEXTAREA' || target.isContentEditable || isPluginViewEditingTarget(target);
     const isMonacoElement =
       target instanceof HTMLElement &&
       !!target.closest?.('.monaco-editor, .monaco-diff-editor, .monaco-inputbox');
@@ -1137,11 +1138,18 @@ export function handleCreateLocalTerminalImpl(
   const { addConnectionLog, classifyLocalShellType, createLocalTerminal, discoveredShells, resolveShellSetting, systemInfoRef, terminalSettings } = getCtx();
 {
     const { username, hostname } = systemInfoRef.current;
-    const resolved = shell ?? resolveShellSetting(terminalSettings.localShell, discoveredShells, terminalSettings.localShellArgs);
+    // Vault/header buttons historically wired `onClick={handleCreateLocalTerminal}`.
+    // React then passes the MouseEvent as the first arg; treat only real shell
+    // objects (string command) as explicit so Settings localShell still applies (#4085).
+    const explicitShell = shell && typeof shell.command === 'string' ? shell : undefined;
+    const resolved = explicitShell
+      ?? resolveShellSetting(terminalSettings.localShell, discoveredShells, terminalSettings.localShellArgs);
     // Match by ID (not command) to avoid WSL distros all sharing wsl.exe
-    const matchedShell = !shell ? discoveredShells.find(s => s.id === terminalSettings.localShell) : undefined;
-    const shellName = shell?.name ?? matchedShell?.name;
-    const shellIcon = shell?.icon ?? matchedShell?.icon;
+    const matchedShell = !explicitShell
+      ? discoveredShells.find(s => s.id === terminalSettings.localShell)
+      : undefined;
+    const shellName = explicitShell?.name ?? matchedShell?.name;
+    const shellIcon = explicitShell?.icon ?? matchedShell?.icon;
     const sessionId = createLocalTerminal({
       shellType: classifyLocalShellType(resolved?.command || terminalSettings.localShell, navigator.userAgent),
       shell: resolved?.command,
@@ -1271,16 +1279,14 @@ export function hasMultipleProtocolsImpl(getCtx: AppContextGetter, host: Host) {
 }
 
 export function handleHostConnectWithProtocolCheckImpl(getCtx: AppContextGetter, host: Host) {
-  const { handleConnectToHost, hasMultipleProtocols, resolveEffectiveHost, setIsQuickSwitcherOpen, setProtocolSelectHost, setQuickSearch } = getCtx();
+  const { handleConnectToHost, hasMultipleProtocols, resolveEffectiveHost, setIsQuickSwitcherOpen, setProtocolSelectHost } = getCtx();
 {
     if (hasMultipleProtocols(host)) {
       setProtocolSelectHost(resolveEffectiveHost(host));
       setIsQuickSwitcherOpen(false);
-      setQuickSearch('');
     } else {
       handleConnectToHost(host);
       setIsQuickSwitcherOpen(false);
-      setQuickSearch('');
     }
   }
 }

application/app/AppShell.architecture.test.ts

@@ -139,12 +139,21 @@ test('ChromeHost builds from chrome settings + session/vault snapshots', () => {
   assert.doesNotMatch(source, /\buseAppSettingsRuntime\s*\(/);
 });
 
-test('DialogsHost builds from local dialog state + selective vault snapshot', () => {
+test('DialogsHost builds from local dialog state without vault runtime hooks', () => {
   const source = hostSources['DialogsHost.tsx'];
   assert.ok(source, 'application/app/hosts/DialogsHost.tsx must exist');
-  assert.match(source, /useVaultSnapshot|useVaultSnapshotField|getVaultSnapshot/);
   assert.doesNotMatch(source, /\buseVaultState\s*\(/);
   assert.doesNotMatch(source, /\buseAppVaultRuntime\s*\(/);
+  // Quick switcher search is owned by QuickSwitcherOverlay; republishing the
+  // dialogs bag per keystroke re-rendered the whole shell.
+  assert.doesNotMatch(source, /quickSearch|getHostSearchMatch/);
+});
+
+test('QuickSwitcherOverlay owns the quick switcher query', () => {
+  const overlay = readFileSync(join(here, 'QuickSwitcherOverlay.tsx'), 'utf8');
+  assert.match(overlay, /useState\(''\)/);
+  const store = readFileSync(join(here, 'appLocalUiStore.ts'), 'utf8');
+  assert.doesNotMatch(store, /quickSearch/);
 });
 
 test('AppSideEffects may use runtime hooks; App must not', () => {

application/app/AppSideEffects.tsx

@@ -1,5 +1,5 @@
 import React, { useCallback, useEffect, useEffectEvent, useLayoutEffect, useMemo, useRef, useState } from 'react';
-import { registerAppHandlers } from './appHandlersBridge';
+import { registerAppHandlers, stabilizeAppHandlers, type StableAppHandlerCache } from './appHandlersBridge';
 import { publishAppLocalUi } from './appLocalUiStore';
 import { activeTabStore, toEditorTabId, fromEditorTabId, isEditorTabId } from '../state/activeTabStore';
 import { useAutoSync } from '../state/useAutoSync';
@@ -19,6 +19,8 @@ import {
 } from '../state/connectionLogsStore';
 import { getNotesSnapshot } from '../state/notesStore';
 import { useVaultAgentBridge } from '../state/useVaultAgentBridge';
+import { terminalReconnectRegistry } from '../state/terminalReconnectRegistry';
+import { requestAgentSessionReconnect } from '../state/agentSessionReconnect';
 import { useWindowControls } from '../state/useWindowControls';
 import { useTerminalKeyboardFocus } from '../state/useTerminalKeyboardFocus';
 import { editorTabStore, useEditorTabChromeList } from '../state/editorTabStore';
@@ -59,6 +61,7 @@ import { collectSessionIds } from '../../domain/workspace';
 import { resolveAgentHostWorkspace } from '../../domain/agentHostWorkspace';
 import { useHostOpenSessionReuse } from '../state/useHostOpenSessionReuse';
 import type { PaneMagnificationController } from '../../domain/paneMagnification';
+import { isPluginViewEditingTarget } from '../state/pluginKeybindings';
 import { resolveCloseIntent } from '../state/resolveCloseIntent';
 import { resolveSnippetsShortcutIntent } from '../state/resolveSnippetsShortcutIntent';
 import { isPrimaryModifierWBinding, resolveWindowCommandCloseIntent } from '../state/windowCommandClose';
@@ -133,7 +136,6 @@ export function AppSideEffects() {
     | { mode: 'create' }
     | null
   >(null);
-  const [quickSearch, setQuickSearch] = useState('');
   // Protocol selection dialog state for QuickSwitcher
   const [protocolSelectHost, setProtocolSelectHost] = useState<Host | null>(null);
   // Navigation state for VaultView sections
@@ -1156,6 +1158,8 @@ export function AppSideEffects() {
     const topmostOpenDialog = openDialogs[openDialogs.length - 1] ?? null;
     const topmostDialogClose = topmostOpenDialog?.querySelector<HTMLElement>('[data-dialog-close="true"]');
 
+    if (!topmostDialogClose && isPluginViewEditingTarget(document.activeElement)) return;
+
     const intent = resolveWindowCommandCloseIntent({
       activeTabId: activeTabStore.getActiveTabId(),
       editorTabIds: editorTabs.map((tab) => toEditorTabId(tab.id)),
@@ -1524,6 +1528,19 @@ export function AppSideEffects() {
     sessions, hosts, keys, identities, resolveEffectiveHost,
   });
 
+  const reconnectSessionForVaultAgent = useCallback((sessionId: string) => {
+    const session = sessions.find((entry) => entry.id === sessionId);
+    return requestAgentSessionReconnect(sessionId, session?.status, terminalReconnectRegistry);
+  }, [sessions]);
+
+  const inspectSessionRecoveryForVaultAgent = useCallback((sessionId: string) => {
+    const session = sessions.find((entry) => entry.id === sessionId);
+    if (!session) return { ok: false, error: `Session "${sessionId}" was not found.` };
+    const live = terminalReconnectRegistry.inspect(sessionId);
+    return { ok: true, sessionId, status: session.status, waitingForInput: false,
+      reconnecting: false, reconnectAllowed: false, ...live };
+  }, [sessions]);
+
   const closeSessionForVaultAgent = useCallback((sessionId: string) => {
     if (!sessions.some((session) => session.id === sessionId)) {
       return { ok: false as const, error: `Session "${sessionId}" was not found.` };
@@ -1568,6 +1585,8 @@ export function AppSideEffects() {
     openHost: openHostForVaultAgent,
     findExistingSessionForHost: findExistingSessionForHostForVaultAgent,
     closeSession: closeSessionForVaultAgent,
+    reconnectSession: reconnectSessionForVaultAgent,
+    inspectSessionRecovery: inspectSessionRecoveryForVaultAgent,
     getScriptSessionMeta: (sessionId) => sessions.find((session) => session.id === sessionId),
   });
 
@@ -1944,7 +1963,7 @@ export function AppSideEffects() {
   const hasMultipleProtocols = useCallback((host: Host) => { return hasMultipleProtocolsImpl(() => ({ host, resolveEffectiveHost }), host); }, [resolveEffectiveHost]);
 
   // Handle host connect with protocol selection (used by QuickSwitcher)
-  const handleHostConnectWithProtocolCheck = useCallback((host: Host) => { return handleHostConnectWithProtocolCheckImpl(() => ({ handleConnectToHost, hasMultipleProtocols, host, resolveEffectiveHost, setIsQuickSwitcherOpen, setProtocolSelectHost, setQuickSearch }), host); }, [hasMultipleProtocols, handleConnectToHost, resolveEffectiveHost]);
+  const handleHostConnectWithProtocolCheck = useCallback((host: Host) => { return handleHostConnectWithProtocolCheckImpl(() => ({ handleConnectToHost, hasMultipleProtocols, host, resolveEffectiveHost, setIsQuickSwitcherOpen, setProtocolSelectHost }), host); }, [hasMultipleProtocols, handleConnectToHost, resolveEffectiveHost]);
 
   // Handle protocol selection from dialog
   const handleProtocolSelect = useCallback((protocol: HostProtocol, port: number) => { return handleProtocolSelectImpl(() => ({ handleConnectToHost, port, protocol, protocolSelectHost, setProtocolSelectHost }), protocol, port); }, [protocolSelectHost, handleConnectToHost]);
@@ -2012,8 +2031,11 @@ export function AppSideEffects() {
 
   // Hosts assemble domain bags from stores + this flat glue. Do NOT register
   // catalog arrays or prepared vault/terminal/chrome/dialogs domain bags here.
+  // Handlers are registered behind stable per-key wrappers so session/host
+  // churn does not re-notify every Host (see stabilizeAppHandlers).
+  const appHandlerCacheRef = useRef<StableAppHandlerCache>(new Map());
   useLayoutEffect(() => {
-    registerAppHandlers({
+    registerAppHandlers(stabilizeAppHandlers(appHandlerCacheRef.current, {
       // Vault glue
       handleAddKnownHost,
       handleDeleteHost,
@@ -2073,15 +2095,13 @@ export function AppSideEffects() {
       setIsCreateWorkspaceOpen,
       setIsQuickSwitcherOpen,
       setProtocolSelectHost,
-      setQuickSearch,
       handleCancelDeleteHost,
       handleConfirmDeleteHost,
-    });
+    }));
     publishAppLocalUi({
       isQuickSwitcherOpen,
       isCreateWorkspaceOpen,
       addToWorkspaceDialog,
-      quickSearch,
       protocolSelectHost,
       navigateToSection,
       deepLinkHostDraft,
@@ -2147,7 +2167,6 @@ export function AppSideEffects() {
     isQuickSwitcherOpen,
     isCreateWorkspaceOpen,
     addToWorkspaceDialog,
-    quickSearch,
     protocolSelectHost,
     navigateToSection,
     deepLinkHostDraft,

application/app/AppView.tsx

@@ -46,6 +46,7 @@ import { getAvailablePaneMagnificationController } from '../../domain/paneMagnif
 import { pluginViewTabStore, usePluginViewTabs } from '../state/pluginViewTabStore';
 import { buildPluginSettingScopeCatalog } from '../state/usePluginSettingScopeCatalog';
 import { useWorkSurfaceHostEditor } from '../state/useWorkSurfaceHostEditor';
+import { QuickSwitcherOverlay } from './QuickSwitcherOverlay';
 import {
   appViewDomainsEqual,
   mergeAppViewDomains,
@@ -53,9 +54,6 @@ import {
 } from './appViewDomains';
 
 const LazyProtocolSelectDialog = lazy(() => import('../../components/ProtocolSelectDialog'));
-const LazyQuickSwitcher = lazy(() =>
-  import('../../components/QuickSwitcher').then((m) => ({ default: m.QuickSwitcher })),
-);
 const LazyCreateWorkspaceDialog = lazy(() =>
   import('../../components/CreateWorkspaceDialog').then((m) => ({ default: m.CreateWorkspaceDialog })),
 );
@@ -63,6 +61,9 @@ const LazyTextEditorTabView = lazy(() =>
   import('../../components/editor/TextEditorTabView').then((m) => ({ default: m.TextEditorTabView })),
 );
 
+// Module-level so TopTabs' memo comparator sees a stable callback.
+const focusEditorWindowTab = (id: string) => { void focusEditorInWindow(id); };
+
 const TextEditorTabFallback = ({ tabId }: { tabId: string }) => {
   const isVisible = useIsEditorTabActive(tabId);
   const hostTreeLayoutWidth = useTerminalHostTreeLayoutWidth();
@@ -242,12 +243,10 @@ function AppViewInner({ domains }: AppViewProps) {
     setIsCreateWorkspaceOpen,
     setIsQuickSwitcherOpen,
     setProtocolSelectHost,
-    setQuickSearch,
   } = ctx;
 
   const dismissTransientOverlays = useCallback(() => {
     setIsQuickSwitcherOpen(false);
-    setQuickSearch('');
     setIsCreateWorkspaceOpen(false);
     setProtocolSelectHost(null);
     setAddToWorkspaceDialog(null);
@@ -260,7 +259,6 @@ function AppViewInner({ domains }: AppViewProps) {
     setIsCreateWorkspaceOpen,
     setIsQuickSwitcherOpen,
     setProtocolSelectHost,
-    setQuickSearch,
   ]);
 
   useMainWindowInputFocusRecovery({ onPageHidden: dismissTransientOverlays });
@@ -277,7 +275,7 @@ function AppViewInner({ domains }: AppViewProps) {
     handleRequestCloseEditorTabRef, handleSessionStatusChange, handleSyncNowManual, handleTerminalDataCapture, handleUpdateHostFromTerminal,
     hostById, hosts, terminalHosts, updateTerminalHosts, hotkeyScheme, identities, importOrReuseKey, isBroadcastEnabled, isComposeSendToAll, onToggleComposeSendTarget, isGlobalBroadcastEnabled, isGlobalComposeSendToAll, onToggleGlobalBroadcast, onToggleGlobalComposeSendTarget, canUseGlobalBroadcast, isCreateWorkspaceOpen, isMacClient, isQuickSwitcherOpen,
     keyBindings, keyboardInteractiveQueue, keys, logViews, managedSources, navigateToSection, openLogView, openNoteRequest, orderedTabsWithEditors, orphanSessions,
-    passphraseQueue, fidoPromptQueue, protocolSelectHost, proxyProfiles, portForwardingRules, quickResults, quickSearch, removeSessionFromWorkspace, reorderWorkTabs, reorderWorkspaceSessions,
+    passphraseQueue, fidoPromptQueue, protocolSelectHost, proxyProfiles, portForwardingRules, removeSessionFromWorkspace, reorderWorkTabs, reorderWorkspaceSessions,
     resolveEmptyVaultConflict, resolveSessionAppearance, runSnippet, sessionLogsDir, sessionLogsEnabled, sessionLogsFormat, sessionLogsTimestampsEnabled, sessionRenameTarget, sshDebugLogsEnabled,
     sessions, setActiveTabId, setDeepLinkHostDraft, setDraggingSessionId, setEditorWordWrap,
     setNavigateToSection, setTerminalFontFamilyId, setTerminalFontSize, setVaultFocusRequest, updateSessionFontSize, updateSessionRestoreCwd, updateSessionDynamicTitle, updateSessionCodingCliProvider, clearSessionFontSizeOverride,
@@ -506,6 +504,16 @@ function AppViewInner({ domains }: AppViewProps) {
     await popOutEditorTab(id, host?.label);
   }, [hostById]);
 
+  // Stable editor-tab callbacks so memoized TextEditorTabView/TextEditorPane
+  // skip re-rendering when unrelated AppView state changes.
+  const requestCloseEditorTabFromView = useCallback(
+    (id: string) => handleRequestCloseEditorTabRef.current(id),
+    [handleRequestCloseEditorTabRef],
+  );
+  const popOutEditorTabFromView = useCallback((id: string) => {
+    void handlePopOutEditorTab(id);
+  }, [handlePopOutEditorTab]);
+
   const handleSaveSessionRename = useCallback((name: string) => {
     if (!sessionRenameTarget) return;
     if (!name.trim()) return;
@@ -583,7 +591,7 @@ function AppViewInner({ domains }: AppViewProps) {
         onClosePluginViewTab={closePluginViewTab}
         onRequestCloseEditorTab={handleRequestCloseEditorTab}
         onPopOutEditorTab={handlePopOutEditorTab}
-        onFocusEditorWindowTab={(id) => { void focusEditorInWindow(id); }}
+        onFocusEditorWindowTab={focusEditorWindowTab}
         hostById={hostById}
       />
 
@@ -847,8 +855,8 @@ function AppViewInner({ domains }: AppViewProps) {
                 hotkeyScheme={hotkeyScheme}
                 keyBindings={keyBindings}
                 hostById={hostById}
-                onRequestClose={(id) => handleRequestCloseEditorTabRef.current(id)}
-                onPopOut={(id) => { void handlePopOutEditorTab(id); }}
+                onRequestClose={requestCloseEditorTabFromView}
+                onPopOut={popOutEditorTabFromView}
               />
             </Suspense>
           </LazyLoadBoundary>
@@ -937,50 +945,39 @@ function AppViewInner({ domains }: AppViewProps) {
       )}
 
       {isQuickSwitcherOpen && (
-        <LazyLoadBoundary name="Quick switcher" resetKey={quickSearch}>
-          <Suspense fallback={null}>
-            <LazyQuickSwitcher
-              isOpen={isQuickSwitcherOpen}
-              query={quickSearch}
-              results={quickResults}
-              sessions={sessions}
-              workspaces={workspaces}
-              showSftpTab={showSftpTab}
-              onQueryChange={setQuickSearch}
-              onSelect={handleHostConnectWithProtocolCheck}
-              onQuickConnect={openQuickConnectFromInput}
-              onEditHost={(host) => {
-                setIsQuickSwitcherOpen(false);
-                setQuickSearch('');
-                handleEditHostFromOverlay(host);
-              }}
-              onSelectTab={(tabId) => {
-                setActiveTabId(tabId);
-                setIsQuickSwitcherOpen(false);
-                setQuickSearch('');
-              }}
-              onCreateLocalTerminal={(shell) => {
-                handleCreateLocalTerminal(shell);
-                setIsQuickSwitcherOpen(false);
-                setQuickSearch('');
-              }}
-              onCreateWorkspace={() => {
-                setIsQuickSwitcherOpen(false);
-                setQuickSearch('');
-                setAddToWorkspaceDialog({ mode: 'create' });
-              }}
-              onClose={() => {
-                setIsQuickSwitcherOpen(false);
-                setQuickSearch('');
-              }}
-              keyBindings={keyBindings}
-              terminalSettings={terminalSettings}
-              paneMagnificationState={paneMagnificationState}
-              onMagnifyCurrentPane={handleMagnifyCurrentPane}
-              onRestoreMagnifiedPane={handleRestoreMagnifiedPane}
-            />
-          </Suspense>
-        </LazyLoadBoundary>
+        <QuickSwitcherOverlay
+          hosts={hosts}
+          isOpen={isQuickSwitcherOpen}
+          sessions={sessions}
+          workspaces={workspaces}
+          showSftpTab={showSftpTab}
+          onSelect={handleHostConnectWithProtocolCheck}
+          onQuickConnect={openQuickConnectFromInput}
+          onEditHost={(host) => {
+            setIsQuickSwitcherOpen(false);
+            handleEditHostFromOverlay(host);
+          }}
+          onSelectTab={(tabId) => {
+            setActiveTabId(tabId);
+            setIsQuickSwitcherOpen(false);
+          }}
+          onCreateLocalTerminal={(shell) => {
+            handleCreateLocalTerminal(shell);
+            setIsQuickSwitcherOpen(false);
+          }}
+          onCreateWorkspace={() => {
+            setIsQuickSwitcherOpen(false);
+            setAddToWorkspaceDialog({ mode: 'create' });
+          }}
+          onClose={() => {
+            setIsQuickSwitcherOpen(false);
+          }}
+          keyBindings={keyBindings}
+          terminalSettings={terminalSettings}
+          paneMagnificationState={paneMagnificationState}
+          onMagnifyCurrentPane={handleMagnifyCurrentPane}
+          onRestoreMagnifiedPane={handleRestoreMagnifiedPane}
+        />
       )}
 
       <RenameDraftDialog

application/app/QuickSwitcherOverlay.tsx

@@ -0,0 +1,48 @@
+import React, { Suspense, lazy, useMemo, useState } from 'react';
+
+import type { QuickSwitcherProps } from '../../components/QuickSwitcher';
+import { LazyLoadBoundary } from '../../components/ui/lazy-load-boundary';
+import { getHostSearchMatch } from '../../lib/searchMatcher';
+import type { Host } from '../../types';
+
+const LazyQuickSwitcher = lazy(() =>
+  import('../../components/QuickSwitcher').then((m) => ({ default: m.QuickSwitcher })),
+);
+
+/** Hosts matching the quick switcher query, best match first. */
+export function filterQuickSwitcherHosts(hosts: Host[], query: string): Host[] {
+  const term = query.trim();
+  if (!term) return hosts;
+  return hosts
+    .map((host) => ({ host, match: getHostSearchMatch(term, host) }))
+    .filter((entry) => entry.match.matched)
+    .sort((left, right) => {
+      if (left.match.score !== right.match.score) {
+        return right.match.score - left.match.score;
+      }
+      return left.host.label.localeCompare(right.host.label);
+    })
+    .map((entry) => entry.host);
+}
+
+export type QuickSwitcherOverlayProps =
+  Omit<QuickSwitcherProps, 'query' | 'results' | 'onQueryChange'> & { hosts: Host[] };
+
+/**
+ * Owns the quick switcher query. It used to live in AppSideEffects and travel
+ * through the app-local UI store, so every keystroke re-rendered the whole
+ * shell (AppSideEffects, every host island, AppShell, AppView and TopTabs).
+ * The overlay is only mounted while the switcher is open, so closing it resets
+ * the query just like the old `setQuickSearch('')` calls did.
+ */
+export function QuickSwitcherOverlay({ hosts, ...props }: QuickSwitcherOverlayProps) {
+  const [query, setQuery] = useState('');
+  const results = useMemo(() => filterQuickSwitcherHosts(hosts, query), [hosts, query]);
+  return (
+    <LazyLoadBoundary name="Quick switcher" resetKey={query}>
+      <Suspense fallback={null}>
+        <LazyQuickSwitcher {...props} query={query} results={results} onQueryChange={setQuery} />
+      </Suspense>
+    </LazyLoadBoundary>
+  );
+}

application/app/appHandlersBridge.test.ts

@@ -0,0 +1,45 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+
+import {
+  getAppHandlers,
+  registerAppHandlers,
+  stabilizeAppHandlers,
+  subscribeAppHandlers,
+  type StableAppHandlerCache,
+} from './appHandlersBridge';
+
+test('stabilized handlers keep their identity and call the latest implementation', () => {
+  const cache: StableAppHandlerCache = new Map();
+  const ref = { current: 1 };
+  const calls: string[] = [];
+  const first = stabilizeAppHandlers(cache, {
+    closeTabsBatch: (id: string) => calls.push(`v1:${id}`),
+    toggleSidePanelRef: ref,
+  });
+  const second = stabilizeAppHandlers(cache, {
+    closeTabsBatch: (id: string) => calls.push(`v2:${id}`),
+    toggleSidePanelRef: ref,
+  });
+  assert.equal(second.closeTabsBatch, first.closeTabsBatch);
+  assert.equal(second.toggleSidePanelRef, ref, 'non-function values pass through');
+  (first.closeTabsBatch as (id: string) => void)('a');
+  assert.deepEqual(calls, ['v2:a']);
+});
+
+test('the bridge does not notify Hosts when only handler implementations change', () => {
+  const cache: StableAppHandlerCache = new Map();
+  let notified = 0;
+  const unsubscribe = subscribeAppHandlers(() => { notified += 1; });
+  try {
+    registerAppHandlers(stabilizeAppHandlers(cache, { handleDeleteHost: () => 'v1' }));
+    const afterFirst = notified;
+    // A session status change recreated the callback (it closes over hosts).
+    registerAppHandlers(stabilizeAppHandlers(cache, { handleDeleteHost: () => 'v2' }));
+    assert.equal(notified, afterFirst);
+    assert.equal((getAppHandlers()!.handleDeleteHost as () => string)(), 'v2');
+  } finally {
+    unsubscribe();
+    registerAppHandlers(null);
+  }
+});

application/app/appHandlersBridge.ts

@@ -51,6 +51,37 @@ class AppHandlersBridge {
 
 const bridge = new AppHandlersBridge();
 
+export type StableAppHandlerCache = Map<string, { latest: unknown; stable: unknown }>;
+
+/**
+ * Give every function-valued handler a per-key wrapper with a stable identity
+ * that always calls the latest implementation; non-functions (refs) pass
+ * through. Many glue callbacks close over sessions/workspaces/hosts, so their
+ * identities changed on every session status change and host update (connect
+ * bursts, last-connected times), and the bridge re-notified every Host island,
+ * rebuilding all shell bags and re-rendering AppView/TopTabs each time. The
+ * handlers are actions invoked from events, never read during render.
+ */
+export function stabilizeAppHandlers(cache: StableAppHandlerCache, handlers: AppHandlers): AppHandlers {
+  const stableHandlers: AppHandlers = {};
+  for (const [key, value] of Object.entries(handlers)) {
+    if (typeof value !== 'function') {
+      stableHandlers[key] = value;
+      continue;
+    }
+    let entry = cache.get(key);
+    if (!entry) {
+      const created: { latest: unknown; stable: unknown } = { latest: value, stable: null };
+      created.stable = (...args: unknown[]) => (created.latest as (...callArgs: unknown[]) => unknown)(...args);
+      cache.set(key, created);
+      entry = created;
+    }
+    entry.latest = value;
+    stableHandlers[key] = entry.stable;
+  }
+  return stableHandlers;
+}
+
 export function registerAppHandlers(handlers: AppHandlers | null): void {
   bridge.set(handlers);
 }

application/app/appLocalUiStore.ts

@@ -24,7 +24,6 @@ export type AppLocalUiSnapshot = {
     | { mode: 'append'; workspaceId: string }
     | { mode: 'create' }
     | null;
-  quickSearch: string;
   protocolSelectHost: Host | null;
   navigateToSection: VaultSection | null;
   deepLinkHostDraft: Host | null;
@@ -43,7 +42,6 @@ export const EMPTY_APP_LOCAL_UI: AppLocalUiSnapshot = Object.freeze({
   isQuickSwitcherOpen: false,
   isCreateWorkspaceOpen: false,
   addToWorkspaceDialog: null,
-  quickSearch: '',
   protocolSelectHost: null,
   navigateToSection: null,
   deepLinkHostDraft: null,
@@ -76,7 +74,6 @@ class AppLocalUiStore {
       prev.isQuickSwitcherOpen === next.isQuickSwitcherOpen
       && prev.isCreateWorkspaceOpen === next.isCreateWorkspaceOpen
       && prev.addToWorkspaceDialog === next.addToWorkspaceDialog
-      && prev.quickSearch === next.quickSearch
       && prev.protocolSelectHost === next.protocolSelectHost
       && prev.navigateToSection === next.navigateToSection
       && prev.deepLinkHostDraft === next.deepLinkHostDraft

application/app/hosts/DialogsHost.tsx

@@ -1,9 +1,6 @@
 import { useLayoutEffect, useMemo, useSyncExternalStore } from 'react';
 
-import { getHostSearchMatch } from '../../../lib/searchMatcher';
-import type { Host } from '../../../types';
 import { useEditorTabChromeList } from '../../state/editorTabStore';
-import { useVaultSnapshot } from '../../state/vaultSnapshotStore';
 import { getAppHandlers, subscribeAppHandlers } from '../appHandlersBridge';
 import {
   publishAppShellDomainSlice,
@@ -11,16 +8,14 @@ import {
 } from '../appShellPropsStore';
 import { useAppLocalUiStore } from '../appLocalUiStore';
 
-const EMPTY_HOST_RESULTS: Host[] = [];
-
 /**
- * Dialogs island: local dialog/queue state from `appLocalUiStore`, plus a
- * selective vault hosts subscription for quick-search results when open.
+ * Dialogs island: local dialog/queue state from `appLocalUiStore`. The quick
+ * switcher owns its query and host results (QuickSwitcherOverlay), so typing
+ * there no longer republishes this bag.
  * Assembles dialogs + overlays field-by-field — never spreads a prepared bag.
  */
 export function DialogsHost() {
   const local = useAppLocalUiStore();
-  const vault = useVaultSnapshot();
   const editorTabs = useEditorTabChromeList();
   const handlers = useSyncExternalStore(
     subscribeAppHandlers,
@@ -28,22 +23,6 @@ export function DialogsHost() {
     getAppHandlers,
   );
 
-  const quickResults = useMemo(() => {
-    if (!local.isQuickSwitcherOpen) return EMPTY_HOST_RESULTS;
-    const term = local.quickSearch.trim();
-    if (!term) return vault.hosts as Host[];
-    return (vault.hosts as Host[])
-      .map((host) => ({ host, match: getHostSearchMatch(term, host) }))
-      .filter((entry) => entry.match.matched)
-      .sort((left, right) => {
-        if (left.match.score !== right.match.score) {
-          return right.match.score - left.match.score;
-        }
-        return left.host.label.localeCompare(right.host.label);
-      })
-      .map((entry) => entry.host);
-  }, [local.isQuickSwitcherOpen, local.quickSearch, vault.hosts]);
-
   const dialogsDomain = useMemo(() => {
     if (!handlers) return null;
     return {
@@ -68,14 +47,11 @@ export function DialogsHost() {
       passphraseQueue: local.passphraseQueue,
       fidoPromptQueue: local.fidoPromptQueue,
       protocolSelectHost: local.protocolSelectHost,
-      quickResults,
-      quickSearch: local.quickSearch,
       resolveEmptyVaultConflict: handlers.resolveEmptyVaultConflict,
       setAddToWorkspaceDialog: handlers.setAddToWorkspaceDialog,
       setIsCreateWorkspaceOpen: handlers.setIsCreateWorkspaceOpen,
       setIsQuickSwitcherOpen: handlers.setIsQuickSwitcherOpen,
       setProtocolSelectHost: handlers.setProtocolSelectHost,
-      setQuickSearch: handlers.setQuickSearch,
     };
   }, [
     editorTabs,
@@ -88,8 +64,6 @@ export function DialogsHost() {
     local.passphraseQueue,
     local.fidoPromptQueue,
     local.protocolSelectHost,
-    local.quickSearch,
-    quickResults,
   ]);
 
   const overlays = useMemo(() => {

application/app/monitorRuntimeIsolation.test.ts

@@ -14,7 +14,22 @@ function loadComponent(path: string, name: string, bindings: Record<string, unkn
   const code = ts.transpile(declaration.getText(ast).replace(/^export /, ''), {
     target: ts.ScriptTarget.ES2022, jsx: ts.JsxEmit.React,
   });
-  return vm.runInNewContext(`${code}; ${name}`, { React, ...bindings }) as React.ComponentType;
+  // Extracting the function drops imports, so inject bare React hooks/APIs into the sandbox.
+  return vm.runInNewContext(`${code}; ${name}`, {
+    React,
+    useState: React.useState,
+    useEffect: React.useEffect,
+    useLayoutEffect: React.useLayoutEffect,
+    useMemo: React.useMemo,
+    useCallback: React.useCallback,
+    useRef: React.useRef,
+    useReducer: React.useReducer,
+    useContext: React.useContext,
+    memo: React.memo,
+    createElement: React.createElement,
+    Fragment: React.Fragment,
+    ...bindings,
+  }) as React.ComponentType;
 }
 
 test('monitor controls update their runtime without rendering unrelated app siblings', async () => {
@@ -32,6 +47,7 @@ test('monitor controls update their runtime without rendering unrelated app sibl
   };
   const MonitorRuntimeHost = loadComponent('./MonitorRuntimeHost.tsx', 'MonitorRuntimeHost', { useMonitorRuntime });
   const App = loadComponent('../../App.tsx', 'App', {
+    performance: { mark: () => {} },
     useMonitorRuntime,
     MonitorRuntimeHost,
     AppLocalStateProvider: ({ children }: { children: React.ReactNode }) => children,

application/app/startupBundle.architecture.test.ts

@@ -0,0 +1,39 @@
+import assert from 'node:assert/strict';
+import { readFileSync } from 'node:fs';
+import { dirname, join } from 'node:path';
+import test from 'node:test';
+import { fileURLToPath } from 'node:url';
+
+// Guards for what the startup bundle (index.html entry) may pull in. Each of
+// these used to land in the entry chunk that every window parses at launch.
+const root = join(dirname(fileURLToPath(import.meta.url)), '..', '..');
+const read = (path: string) => readFileSync(join(root, path), 'utf8');
+const staticImports = (source: string) =>
+  [...source.matchAll(/^\s*import\s+(?!type\b)[^;]*?from\s+['"]([^'"]+)['"]/gm)].map((match) => match[1]);
+
+test('only the English dictionary is bundled with the startup entry', () => {
+  const imports = staticImports(read('application/i18n/messages.ts'));
+  assert.deepEqual(imports.filter((path) => path.startsWith('./locales/')), ['./locales/en']);
+});
+
+test('startup modules do not statically import the AI runtime or SDK providers', () => {
+  const runtimeModules = /harness\/globalAgentRuntime|plugin\/trustedHostRuntime|plugin\/configuredModel|pluginAgent\/trustedAgentRuntime|sdk\/providers/;
+  for (const path of [
+    'application/state/aiStateSnapshots.ts',
+    'application/state/usePluginAIContextHost.ts',
+    'application/state/usePluginAgentHost.ts',
+  ]) {
+    const offending = staticImports(read(path)).filter((specifier) => runtimeModules.test(specifier));
+    assert.deepEqual(offending, [], `${path} must load the AI runtime lazily`);
+  }
+});
+
+test("Vite's preload helper stays out of the vendor-ai chunk", () => {
+  // The entry imports the helper for its dynamic imports; if it is grouped
+  // with the AI SDK, the whole vendor-ai chunk is preloaded at startup.
+  assert.match(read('vite.config.ts'), /vite\/preload-helper'\)\) return 'preload-helper'/);
+});
+
+test('the QR decoder is loaded on demand', () => {
+  assert.ok(!staticImports(read('components/HostTotpFields.tsx')).includes('jsqr'));
+});

application/app/useAppStartupEffects.ts

@@ -293,7 +293,10 @@ export function useAppStartupEffects(ctx: StartupEffectsContext) {
     terminalSettings,
   });
 
-  // Sync tray menu data + handle tray actions
+  // Sync tray menu data + handle tray actions. Hosts are only re-sent when the
+  // host list changed: session status updates (connect bursts) used to resend
+  // and re-serialize every host and rebuild the macOS Dock menu each time.
+  const lastTrayHostsRef = useRef<unknown>(null);
   useEffect(() => {
     if (!enabled) return;
     const bridge = netcattyBridge.get();
@@ -316,17 +319,21 @@ export function useAppStartupEffects(ctx: StartupEffectsContext) {
         };
       });
 
-      const hostsForSystemMenu = hosts
-        .filter((host: any) => typeof host?.id === "string" && host.id.length > 0)
-        .map((host: any) => ({
-          id: host.id,
-          label: host.label,
-          hostname: host.hostname,
-          group: host.group,
-          pinned: host.pinned,
-          lastConnectedAt: host.lastConnectedAt,
-          protocol: host.protocol,
-        }));
+      const hostsChanged = lastTrayHostsRef.current !== hosts;
+      lastTrayHostsRef.current = hosts;
+      const hostsForSystemMenu = hostsChanged
+        ? hosts
+          .filter((host: any) => typeof host?.id === "string" && host.id.length > 0)
+          .map((host: any) => ({
+            id: host.id,
+            label: host.label,
+            hostname: host.hostname,
+            group: host.group,
+            pinned: host.pinned,
+            lastConnectedAt: host.lastConnectedAt,
+            protocol: host.protocol,
+          }))
+        : undefined;
 
       void bridge.updateTrayMenuData({
         sessions: sessionsForTray,
@@ -334,7 +341,7 @@ export function useAppStartupEffects(ctx: StartupEffectsContext) {
           ...rule,
           canStop: hasRuntimeTunnel(rule.id),
         })),
-        hosts: hostsForSystemMenu,
+        ...(hostsForSystemMenu ? { hosts: hostsForSystemMenu } : {}),
       });
     }, 250);
 

application/i18n/I18nProvider.tsx

@@ -1,6 +1,13 @@
-import React, { createContext, useContext, useMemo } from 'react';
+import React, { createContext, useContext, useEffect, useMemo, useSyncExternalStore } from 'react';
 import { DEFAULT_UI_LOCALE, resolveSupportedLocale } from '../../infrastructure/config/i18n';
-import { MESSAGES_BY_LOCALE } from './messages';
+import {
+  getBaseFallbackLocale,
+  getLoadedLocaleMessages,
+  getLocaleMessagesVersion,
+  loadLocaleMessages,
+  subscribeLocaleMessages,
+  type Messages,
+} from './messages';
 
 type InterpolationValues = Record<string, string | number | boolean | null | undefined>;
 
@@ -29,32 +36,59 @@ const interpolate = (template: string, values?: InterpolationValues): string =>
     .replace(/\{(\w+)\}/g, replaceSingleBraceToken);
 };
 
-const resolveMessage = (resolvedLocale: string, key: string): string | undefined => {
-  const direct = MESSAGES_BY_LOCALE[resolvedLocale]?.[key];
-  if (direct) return direct;
-  const base = resolvedLocale.split('-')[0];
-  const baseKey = Object.keys(MESSAGES_BY_LOCALE).find((k) => k === base || k.startsWith(`${base}-`));
-  const baseHit = baseKey ? MESSAGES_BY_LOCALE[baseKey]?.[key] : undefined;
-  if (baseHit) return baseHit;
-  return MESSAGES_BY_LOCALE[DEFAULT_UI_LOCALE]?.[key];
+type LocaleDictionaries = {
+  direct?: Messages;
+  base?: Messages;
+  fallback?: Messages;
 };
 
+/**
+ * Dictionaries consulted for `resolvedLocale`: exact locale, same-base sibling
+ * (zh-TW -> zh-CN), then English. `_loadedVersion` is only a cache key so a
+ * dictionary that finishes loading yields a fresh snapshot.
+ */
+const snapshotLocaleDictionaries = (resolvedLocale: string, _loadedVersion: number): LocaleDictionaries => {
+  const baseKey = getBaseFallbackLocale(resolvedLocale);
+  return {
+    direct: getLoadedLocaleMessages(resolvedLocale),
+    base: baseKey ? getLoadedLocaleMessages(baseKey) : undefined,
+    fallback: getLoadedLocaleMessages(DEFAULT_UI_LOCALE),
+  };
+};
+
+const resolveMessage = (dictionaries: LocaleDictionaries, key: string): string | undefined =>
+  dictionaries.direct?.[key] || dictionaries.base?.[key] || dictionaries.fallback?.[key];
+
 export const I18nProvider: React.FC<{ locale: string; children: React.ReactNode }> = ({
   locale,
   children,
 }) => {
   const resolvedLocale = resolveSupportedLocale(locale || DEFAULT_UI_LOCALE);
+  // Non-English dictionaries load on demand (index.tsx preloads the saved one
+  // before the first render); re-render consumers once a switch finishes.
+  const messagesVersion = useSyncExternalStore(
+    subscribeLocaleMessages,
+    getLocaleMessagesVersion,
+    getLocaleMessagesVersion,
+  );
+  useEffect(() => {
+    void loadLocaleMessages(resolvedLocale).catch(() => {});
+  }, [resolvedLocale]);
+  const dictionaries = useMemo(
+    () => snapshotLocaleDictionaries(resolvedLocale, messagesVersion),
+    [resolvedLocale, messagesVersion],
+  );
 
   const value = useMemo<I18nContextValue>(() => {
     return {
       locale,
       resolvedLocale,
       t: (key, values) => {
-        const msg = resolveMessage(resolvedLocale, key) ?? key;
+        const msg = resolveMessage(dictionaries, key) ?? key;
         return interpolate(msg, values);
       },
     };
-  }, [locale, resolvedLocale]);
+  }, [dictionaries, locale, resolvedLocale]);
 
   return <I18nContext.Provider value={value}>{children}</I18nContext.Provider>;
 };

application/i18n/locales/en/ai.ts

@@ -525,6 +525,8 @@ export const enAiMessages: Messages = {
   'ai.chat.alwaysAllow': 'Always',
   'ai.chat.slashStopDesc': 'Stop the current AI turn and cancel in-flight tools',
   'ai.chat.slashCompactDesc': 'Summarize earlier conversation context',
+  'ai.chat.slashRenameDesc': 'Rename the current chat (/rename <title>)',
+  'ai.chat.slashChatsDesc': 'List the chats visible to this panel',
   'ai.chat.reject': 'Reject',
   'ai.chat.toolLabel': 'Tool',
   'ai.chat.targetLabel': 'Target',
@@ -587,6 +589,28 @@ export const enAiMessages: Messages = {
   'ai.chat.recent': 'Recent',
   'ai.chat.viewAll': 'View All',
   'ai.chat.untitled': 'Untitled',
+  'ai.chat.renameChat': 'Rename chat',
+  'ai.chat.renameUsage': 'Usage: /rename <new title>',
+  'ai.chat.renameNoActive': 'No active chat to rename.',
+  'ai.chat.renameDone': 'Chat renamed to "{title}".',
+  'ai.chat.exportSessions': 'Export AI chats',
+  'ai.chat.importSessions': 'Import AI chats',
+  'ai.chat.exportDone': 'AI chats exported to {path}.',
+  'ai.chat.exportDoneNoPath': 'AI chats exported.',
+  'ai.chat.exportUnavailable': 'AI chat export is unavailable in this environment.',
+  'ai.chat.importDone': 'Imported {n} AI chat(s).',
+  'ai.chat.importNone': 'No AI chats found in the selected file.',
+  'ai.chat.chatsHeader': 'Chats visible in this panel:',
+  'ai.chat.chatsEmpty': 'No chats visible in this panel.',
+  'ai.chat.chatsScopeWorkspace': 'Workspace',
+  'ai.chat.chatsScopeTerminal': 'Terminal',
+  'ai.chat.chatsScopeGlobal': 'Global',
+  'ai.chat.chatsScopeDangling': 'Dissociated',
+  'ai.chat.slashRebindDesc': 'Rebind a disconnected chat to this panel (/rebind <n>)',
+  'ai.chat.chatsRebindHint': 'Disconnected chats can be restored with /rebind <n>.',
+  'ai.chat.rebindUsage': 'Usage: /rebind <number from /chats>',
+  'ai.chat.rebindDone': 'Chat "{title}" rebound to this panel.',
+  'ai.chat.rebindUnavailable': 'No rebind target in this panel scope.',
   'ai.chat.justNow': 'Just now',
   'ai.chat.minutesAgo': '{n}m ago',
   'ai.chat.hoursAgo': '{n}h ago',
@@ -795,4 +819,27 @@ export const enAiMessages: Messages = {
   'zmodem.overwrite.skip': 'Skip',
   'zmodem.overwrite.cancel': 'Cancel',
   'settings.shortcuts.resetToDefault': 'Reset to default',
+  "ai.toolSettings.immediate": "Changes take effect immediately. Closing this window does not undo them.",
+  "ai.toolSettings.privacyOn": "Text redaction enabled",
+  "ai.toolSettings.privacyOff": "Text redaction disabled",
+  "ai.toolSettings.ruleSummary": "{cidrs} additional IP ranges · {patterns} custom patterns",
+  "ai.toolSettings.configurePrivacy": "Configure privacy",
+  "ai.toolSettings.unsaved": "Unsaved changes",
+  "ai.toolSettings.viewSkills": "View CLI guidance",
+  "ai.toolSettings.viewPrompt": "View setup prompt",
+  "ai.toolSettings.behavior": "MCP behavior",
+  "ai.toolSettings.configureBehavior": "Configure behavior",
+  "ai.toolSettings.configureClients": "Configure clients",
+  "ai.toolSettings.httpOn": "HTTP enabled",
+  "ai.toolSettings.httpOff": "HTTP disabled",
+  "ai.toolSettings.loopback": "Local connections only (127.0.0.1)",
+  "ai.toolSettings.configureHttp": "Configure HTTP",
+  "ai.toolSettings.hideSecret": "Hide secret",
+  "ai.toolSettings.showSecret": "Show secret",
+  "ai.toolSettings.manualSetup": "Manual setup",
+  "ai.toolSettings.format": "Format",
+  "ai.toolSettings.connectionDetails": "Connection details",
+  "ai.toolSettings.conflict": "Settings changed in another window. Your draft is preserved. Cancel and reopen to load the saved settings.",
+  "ai.toolSettings.retry": "Retry",
+  "ai.toolSettings.applyingHttp": "Applying HTTP configuration...",
 };

application/i18n/locales/en/core.ts

@@ -161,7 +161,12 @@ export const enCoreMessages: Messages = {
   'settings.system.clearTempFiles': 'Clear temp files',
   'settings.system.clearing': 'Clearing...',
   'settings.system.clearResult': 'Deleted {deleted} file(s), {failed} failed.',
-  'settings.system.tempDirectoryHint': 'Temporary files are created when opening remote files with external applications. They are automatically cleaned up when SFTP sessions close.',
+  'settings.system.tempDirChoose': 'Choose folder',
+  'settings.system.tempDirManual': 'Enter an absolute folder path',
+  'settings.system.tempDirApply': 'Apply',
+  'settings.system.tempDirReset': 'Reset to default',
+  'settings.system.tempDirError': 'Unable to use this folder.',
+  'settings.system.tempDirectoryHint': 'Netcatty creates a Netcatty temp subfolder in the chosen folder for SFTP staging and external editing. Changing the folder during a transfer may affect that transfer.',
   'settings.system.credentials.title': 'Credential Protection',
   'settings.system.credentials.status': 'Status',
   'settings.system.credentials.checking': 'Checking...',
@@ -1375,6 +1380,9 @@ Highlight the focused split pane:
   "settings.plugins.openManager": "Open plugin manager",
   "settings.plugins.sources.conflict": "This ID is installed from another source. Uninstall and explicitly reset its private data before switching. Existing source:",
   "settings.plugins.sources.clearPrivate": "Also clear this source’s private data, grants and secrets to reinstall from another source. This cannot be undone.",
+  "settings.plugins.sources.short.official": "Official",
+  "settings.plugins.sources.short.thirdparty": "Third-party",
+  "settings.plugins.sources.short.local": "Local",
   "settings.plugins.sources.official": "Official marketplace",
   "settings.plugins.sources.thirdparty": "Third-party marketplace",
   "settings.plugins.sources.manage": "Manage sources",
@@ -1393,6 +1401,7 @@ Highlight the focused split pane:
   "settings.plugins.sources.local": "Local import",
   "settings.plugins.sources.all": "All sources",
   "settings.plugins.title": "Plugins",
+  "settings.plugins.configuration": "Plugin settings",
   "settings.plugins.description": "Manage your plugins and explore the catalog.",
   'settings.plugins.loading': 'Loading plugin settings…',
   'settings.plugins.empty': 'No enabled plugin contributes settings.',

application/i18n/locales/en/monitor.ts

@@ -1,4 +1,8 @@
 export const enMonitorMessages = {
+  "monitor.systemDisks": "System partitions ({count})",
+  "monitor.systemDisksAlert": "System partition usage exceeds 80%; expanded automatically.",
+  "monitor.diskIoTotal": "Total",
+  "monitor.partitionIoHint": "I/O of the block device backing this mount. Mounts sharing a device show the same rates. Unavailable until two valid samples or when no block device can be identified; not supported on macOS.",
   "monitor.diskIo": "Disk I/O",
   "monitor.diskRead": "Read",
   "monitor.diskWrite": "Write",

application/i18n/locales/en/terminal.ts

@@ -460,6 +460,7 @@ export const enTerminalMessages: Messages = {
   'cloudSync.localBackups.clearFailed': 'Could not clear all local backups. Please retry.',
   'cloudSync.localBackups.title': 'Local Backup History',
   'cloudSync.localBackups.desc': 'Netcatty keeps local restore points before app version changes and before vault restores.',
+  'cloudSync.localBackups.folderWarning': 'This folder alone is not a complete, portable backup. Deleting or wiping the app profile (userData) may make these restore points unreadable.',
   'cloudSync.localBackups.retentionTitle': 'Backup Retention',
   'cloudSync.localBackups.retentionDesc': 'Choose how many local backups Netcatty should keep.',
   'cloudSync.localBackups.maxCount': 'Max backups',
@@ -474,6 +475,7 @@ export const enTerminalMessages: Messages = {
   'cloudSync.localBackups.restoreSuccess': 'Local backup restored.',
   'cloudSync.localBackups.restoreFailedTitle': 'Restore failed',
   'cloudSync.localBackups.restoreMissing': 'Backup not found.',
+  'cloudSync.localBackups.decryptFailed': 'The current app profile cannot decrypt this backup. The encryption key may be missing, the profile may have changed, or the backup may be damaged.',
   'cloudSync.localBackups.protectiveBackupFailed': 'Safety backup could not be created, so the restore was aborted to protect your current data. Resolve the underlying issue (e.g. keychain access) and try again. Details: {message}',
   'cloudSync.localBackups.restoreConfirmTitle': 'Restore this backup?',
   'cloudSync.localBackups.restoreConfirmDesc': 'Your current hosts, keys, snippets and settings will be replaced with the contents of this backup. A protective snapshot of your current data is taken automatically first.',

application/i18n/locales/es/ai.ts

@@ -525,6 +525,8 @@ export const esAiMessages: Messages = {
   'ai.chat.alwaysAllow': 'Siempre',
   'ai.chat.slashStopDesc': 'Detener el turno actual de IA y cancelar las herramientas en curso',
   'ai.chat.slashCompactDesc': 'Resumir el contexto anterior de la conversación',
+  'ai.chat.slashRenameDesc': 'Renombrar el chat actual (/rename <título>)',
+  'ai.chat.slashChatsDesc': 'Listar los chats visibles en este panel',
   'ai.chat.reject': 'Rechazar',
   'ai.chat.toolLabel': 'Herramienta',
   'ai.chat.targetLabel': 'Destino',
@@ -587,6 +589,28 @@ export const esAiMessages: Messages = {
   'ai.chat.recent': 'Recientes',
   'ai.chat.viewAll': 'Ver todo',
   'ai.chat.untitled': 'Sin título',
+  'ai.chat.renameChat': 'Renombrar chat',
+  'ai.chat.renameUsage': 'Uso: /rename <nuevo título>',
+  'ai.chat.renameNoActive': 'No hay ningún chat activo para renombrar.',
+  'ai.chat.renameDone': 'Chat renombrado a «{title}».',
+  'ai.chat.exportSessions': 'Exportar chats de IA',
+  'ai.chat.importSessions': 'Importar chats de IA',
+  'ai.chat.exportDone': 'Chats de IA exportados a {path}.',
+  'ai.chat.exportDoneNoPath': 'Chats de IA exportados.',
+  'ai.chat.exportUnavailable': 'La exportación de chats de IA no está disponible en este entorno.',
+  'ai.chat.importDone': 'Se importaron {n} chat(s) de IA.',
+  'ai.chat.importNone': 'No se encontraron chats de IA en el archivo seleccionado.',
+  'ai.chat.chatsHeader': 'Chats visibles en este panel:',
+  'ai.chat.chatsEmpty': 'No hay chats visibles en este panel.',
+  'ai.chat.chatsScopeWorkspace': 'Workspace',
+  'ai.chat.chatsScopeTerminal': 'Terminal',
+  'ai.chat.chatsScopeGlobal': 'Global',
+  'ai.chat.chatsScopeDangling': 'Desasociado',
+  'ai.chat.slashRebindDesc': 'Reasociar un chat desconectado a este panel (/rebind <n>)',
+  'ai.chat.chatsRebindHint': 'Los chats desconectados se pueden restaurar con /rebind <n>.',
+  'ai.chat.rebindUsage': 'Uso: /rebind <número de /chats>',
+  'ai.chat.rebindDone': 'Chat «{title}» reasociado a este panel.',
+  'ai.chat.rebindUnavailable': 'No hay destino de reasociación en el ámbito de este panel.',
   'ai.chat.justNow': 'Ahora mismo',
   'ai.chat.minutesAgo': 'hace {n} min',
   'ai.chat.hoursAgo': 'hace {n} h',
@@ -795,4 +819,27 @@ export const esAiMessages: Messages = {
   'zmodem.overwrite.skip': 'Omitir',
   'zmodem.overwrite.cancel': 'Cancelar',
   'settings.shortcuts.resetToDefault': 'Restablecer al predeterminado',
+  "ai.toolSettings.immediate": "Los cambios se aplican inmediatamente. Cerrar esta ventana no los deshace.",
+  "ai.toolSettings.privacyOn": "Ocultación de texto activada",
+  "ai.toolSettings.privacyOff": "Ocultación de texto desactivada",
+  "ai.toolSettings.ruleSummary": "{cidrs} rangos IP adicionales · {patterns} patrones personalizados",
+  "ai.toolSettings.configurePrivacy": "Configurar privacidad",
+  "ai.toolSettings.unsaved": "Cambios sin guardar",
+  "ai.toolSettings.viewSkills": "Ver instrucciones de CLI",
+  "ai.toolSettings.viewPrompt": "Ver instrucciones de conexión",
+  "ai.toolSettings.behavior": "Comportamiento de MCP",
+  "ai.toolSettings.configureBehavior": "Configurar comportamiento",
+  "ai.toolSettings.configureClients": "Configurar clientes",
+  "ai.toolSettings.httpOn": "HTTP activado",
+  "ai.toolSettings.httpOff": "HTTP desactivado",
+  "ai.toolSettings.loopback": "Solo conexiones locales (127.0.0.1)",
+  "ai.toolSettings.configureHttp": "Configurar HTTP",
+  "ai.toolSettings.hideSecret": "Ocultar secreto",
+  "ai.toolSettings.showSecret": "Mostrar secreto",
+  "ai.toolSettings.manualSetup": "Configuración manual",
+  "ai.toolSettings.format": "Formato",
+  "ai.toolSettings.connectionDetails": "Detalles de conexión",
+  "ai.toolSettings.conflict": "La configuración cambió en otra ventana. Se conserva el borrador. Cancela y vuelve a abrir para cargar la configuración guardada.",
+  "ai.toolSettings.retry": "Reintentar",
+  "ai.toolSettings.applyingHttp": "Aplicando la configuración HTTP...",
 };

application/i18n/locales/es/core.ts

@@ -161,7 +161,12 @@ export const esCoreMessages: Messages = {
   'settings.system.clearTempFiles': 'Limpiar archivos temporales',
   'settings.system.clearing': 'Limpiando...',
   'settings.system.clearResult': 'Se eliminaron {deleted} archivo(s), {failed} fallaron.',
-  'settings.system.tempDirectoryHint': 'Los archivos temporales se crean al abrir archivos remotos con aplicaciones externas. Se limpian automáticamente cuando las sesiones SFTP se cierran.',
+  'settings.system.tempDirChoose': 'Elegir carpeta',
+  'settings.system.tempDirManual': 'Introduce una ruta de carpeta absoluta',
+  'settings.system.tempDirApply': 'Aplicar',
+  'settings.system.tempDirReset': 'Restablecer predeterminado',
+  'settings.system.tempDirError': 'No se puede usar esta carpeta.',
+  'settings.system.tempDirectoryHint': 'Se usa para el almacenamiento temporal de transferencias SFTP y archivos abiertos con aplicaciones externas. Cambiar la carpeta durante una transferencia puede afectar esa transferencia.',
   'settings.system.credentials.title': 'Protección de credenciales',
   'settings.system.credentials.status': 'Estado',
   'settings.system.credentials.checking': 'Comprobando...',
@@ -1375,6 +1380,9 @@ Resalta el panel dividido enfocado:
   "settings.plugins.openManager": "Abrir gestor de plugins",
   "settings.plugins.sources.conflict": "This ID is installed from another source. Uninstall and explicitly reset its private data before switching. Existing source:",
   "settings.plugins.sources.clearPrivate": "Also clear this source’s private data, grants and secrets to reinstall from another source. This cannot be undone.",
+  "settings.plugins.sources.short.official": "Oficial",
+  "settings.plugins.sources.short.thirdparty": "Terceros",
+  "settings.plugins.sources.short.local": "Local",
   "settings.plugins.sources.official": "Official marketplace",
   "settings.plugins.sources.thirdparty": "Third-party marketplace",
   "settings.plugins.sources.manage": "Manage sources",
@@ -1393,6 +1401,7 @@ Resalta el panel dividido enfocado:
   "settings.plugins.sources.local": "Local import",
   "settings.plugins.sources.all": "All sources",
   "settings.plugins.title": "Plugins",
+  "settings.plugins.configuration": "Ajustes del plugin",
   "settings.plugins.description": "Gestiona tus plugins y explora el catálogo.",
   'settings.plugins.loading': 'Cargando ajustes del plugin…',
   'settings.plugins.empty': 'Ningún plugin activado aporta ajustes.',

application/i18n/locales/es/monitor.ts

@@ -1,4 +1,8 @@
 export const esMonitorMessages = {
+  "monitor.systemDisks": "Particiones del sistema ({count})",
+  "monitor.systemDisksAlert": "El uso de una partición del sistema supera el 80 %; se ha expandido automáticamente.",
+  "monitor.diskIoTotal": "Total",
+  "monitor.partitionIoHint": "E/S del dispositivo de bloques de este montaje. Los montajes del mismo dispositivo muestran las mismas tasas. No disponible hasta tener dos muestras válidas o sin un dispositivo identificable; no compatible con macOS.",
   "monitor.diskIo": "E/S de disco",
   "monitor.diskRead": "Lectura",
   "monitor.diskWrite": "Escritura",

application/i18n/locales/es/terminal.ts

@@ -460,6 +460,7 @@ export const esTerminalMessages: Messages = {
   'cloudSync.localBackups.clearFailed': 'No se pudieron eliminar todas las copias locales. Inténtalo de nuevo.',
   'cloudSync.localBackups.title': 'Historial de copias de seguridad locales',
   'cloudSync.localBackups.desc': 'Netcatty conserva puntos de restauración locales antes de los cambios de versión de la app y antes de las restauraciones de la bóveda.',
+  'cloudSync.localBackups.folderWarning': 'Esta carpeta por sí sola no es una copia de seguridad completa y portátil. Eliminar o vaciar el perfil de la aplicación (userData) puede impedir la lectura de estos puntos de restauración.',
   'cloudSync.localBackups.retentionTitle': 'Retención de copias de seguridad',
   'cloudSync.localBackups.retentionDesc': 'Elige cuántas copias de seguridad locales debe conservar Netcatty.',
   'cloudSync.localBackups.maxCount': 'Copias máximas',
@@ -474,6 +475,7 @@ export const esTerminalMessages: Messages = {
   'cloudSync.localBackups.restoreSuccess': 'Copia de seguridad local restaurada.',
   'cloudSync.localBackups.restoreFailedTitle': 'Falló la restauración',
   'cloudSync.localBackups.restoreMissing': 'No se encontró la copia de seguridad.',
+  'cloudSync.localBackups.decryptFailed': 'El perfil actual de la aplicación no puede descifrar esta copia. Puede faltar la clave de cifrado, haber cambiado el perfil o estar dañada la copia.',
   'cloudSync.localBackups.protectiveBackupFailed': 'No se pudo crear la copia de seguridad de protección, por lo que la restauración se canceló para proteger tus datos actuales. Resuelve el problema subyacente (p. ej., acceso al keychain) e inténtalo de nuevo. Detalles: {message}',
   'cloudSync.localBackups.restoreConfirmTitle': '¿Restaurar esta copia de seguridad?',
   'cloudSync.localBackups.restoreConfirmDesc': 'Tus hosts, claves, snippets y configuraciones actuales se reemplazarán con el contenido de esta copia de seguridad. Se crea automáticamente una instantánea de protección de tus datos actuales primero.',

application/i18n/locales/lazyLocaleLoading.test.ts

@@ -0,0 +1,36 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+
+import {
+  getBaseFallbackLocale,
+  getLoadedLocaleMessages,
+  getLocaleMessagesVersion,
+  loadLocaleMessages,
+  subscribeLocaleMessages,
+} from '../messages';
+
+test('only English is loaded until another locale is requested', () => {
+  assert.ok(getLoadedLocaleMessages('en'));
+  assert.equal(getLoadedLocaleMessages('ru'), undefined);
+});
+
+test('zh-TW resolves through zh-CN, matching the old static lookup order', () => {
+  assert.equal(getBaseFallbackLocale('zh-TW'), 'zh-CN');
+  assert.equal(getBaseFallbackLocale('zh-CN'), 'zh-CN');
+  assert.equal(getBaseFallbackLocale('es'), 'es');
+  assert.equal(getBaseFallbackLocale('fr'), undefined);
+});
+
+test('loading a locale also loads its fallback and notifies subscribers once each', async () => {
+  const before = getLocaleMessagesVersion();
+  let notified = 0;
+  const unsubscribe = subscribeLocaleMessages(() => { notified += 1; });
+  await Promise.all([loadLocaleMessages('zh-TW'), loadLocaleMessages('zh-TW')]);
+  unsubscribe();
+  assert.ok(getLoadedLocaleMessages('zh-TW'));
+  assert.ok(getLoadedLocaleMessages('zh-CN'), 'base fallback is loaded with zh-TW');
+  assert.equal(notified, 2, 'one notification per newly loaded dictionary');
+  assert.equal(getLocaleMessagesVersion(), before + 2);
+  await loadLocaleMessages('zh-TW');
+  assert.equal(getLocaleMessagesVersion(), before + 2, 'already loaded locales are not reloaded');
+});

application/i18n/locales/ru/ai.ts

@@ -464,6 +464,8 @@ export const ruAiMessages: Messages = {
   'ai.chat.alwaysAllow': 'Всегда разрешать',
   'ai.chat.slashStopDesc': 'Остановить текущий ход AI и отменить выполняющиеся инструменты',
   'ai.chat.slashCompactDesc': 'Сжать ранний контекст разговора',
+  'ai.chat.slashRenameDesc': 'Переименовать текущий чат (/rename <название>)',
+  'ai.chat.slashChatsDesc': 'Показать чаты, видимые в этой панели',
   'ai.chat.reject': 'Отклонить',
   'ai.chat.toolLabel': 'Инструмент',
   'ai.chat.targetLabel': 'Цель',
@@ -526,6 +528,28 @@ export const ruAiMessages: Messages = {
   'ai.chat.recent': 'Недавние',
   'ai.chat.viewAll': 'Показать всё',
   'ai.chat.untitled': 'Без названия',
+  'ai.chat.renameChat': 'Переименовать чат',
+  'ai.chat.renameUsage': 'Использование: /rename <новое название>',
+  'ai.chat.renameNoActive': 'Нет активного чата для переименования.',
+  'ai.chat.renameDone': 'Чат переименован в «{title}».',
+  'ai.chat.exportSessions': 'Экспортировать чаты ИИ',
+  'ai.chat.importSessions': 'Импортировать чаты ИИ',
+  'ai.chat.exportDone': 'Чаты ИИ экспортированы в {path}.',
+  'ai.chat.exportDoneNoPath': 'Чаты ИИ экспортированы.',
+  'ai.chat.exportUnavailable': 'Экспорт чатов ИИ недоступен в этой среде.',
+  'ai.chat.importDone': 'Импортировано чатов ИИ: {n}.',
+  'ai.chat.importNone': 'В выбранном файле не найдено чатов ИИ.',
+  'ai.chat.chatsHeader': 'Чаты, видимые в этой панели:',
+  'ai.chat.chatsEmpty': 'В этой панели нет видимых чатов.',
+  'ai.chat.chatsScopeWorkspace': 'Workspace',
+  'ai.chat.chatsScopeTerminal': 'Терминал',
+  'ai.chat.chatsScopeGlobal': 'Глобально',
+  'ai.chat.chatsScopeDangling': 'Связь потеряна',
+  'ai.chat.slashRebindDesc': 'Привязать потерянный чат к этой панели (/rebind <n>)',
+  'ai.chat.chatsRebindHint': 'Потерянные чаты можно восстановить командой /rebind <n>.',
+  'ai.chat.rebindUsage': 'Использование: /rebind <номер из /chats>',
+  'ai.chat.rebindDone': 'Чат «{title}» привязан к этой панели.',
+  'ai.chat.rebindUnavailable': 'В области этой панели нет цели для привязки.',
   'ai.chat.justNow': 'Только что',
   'ai.chat.minutesAgo': '{n}м назад',
   'ai.chat.hoursAgo': '{n}ч назад',
@@ -724,4 +748,27 @@ export const ruAiMessages: Messages = {
   'zmodem.overwrite.skip': 'Пропустить',
   'zmodem.overwrite.cancel': 'Отмена',
   'settings.shortcuts.resetToDefault': 'Сбросить по умолчанию',
+  "ai.toolSettings.immediate": "Изменения применяются сразу. Закрытие окна не отменяет их.",
+  "ai.toolSettings.privacyOn": "Скрытие текста включено",
+  "ai.toolSettings.privacyOff": "Скрытие текста выключено",
+  "ai.toolSettings.ruleSummary": "Дополнительные диапазоны IP: {cidrs} · Пользовательские шаблоны: {patterns}",
+  "ai.toolSettings.configurePrivacy": "Настроить приватность",
+  "ai.toolSettings.unsaved": "Есть несохранённые изменения",
+  "ai.toolSettings.viewSkills": "Инструкции CLI",
+  "ai.toolSettings.viewPrompt": "Инструкции подключения",
+  "ai.toolSettings.behavior": "Поведение MCP",
+  "ai.toolSettings.configureBehavior": "Настроить поведение",
+  "ai.toolSettings.configureClients": "Настроить клиенты",
+  "ai.toolSettings.httpOn": "HTTP включён",
+  "ai.toolSettings.httpOff": "HTTP выключен",
+  "ai.toolSettings.loopback": "Только локальные подключения (127.0.0.1)",
+  "ai.toolSettings.configureHttp": "Настроить HTTP",
+  "ai.toolSettings.hideSecret": "Скрыть секрет",
+  "ai.toolSettings.showSecret": "Показать секрет",
+  "ai.toolSettings.manualSetup": "Ручная настройка",
+  "ai.toolSettings.format": "Формат",
+  "ai.toolSettings.connectionDetails": "Параметры подключения",
+  "ai.toolSettings.conflict": "Настройки изменены в другом окне. Черновик сохранён. Отмените и откройте окно снова, чтобы загрузить сохранённые настройки.",
+  "ai.toolSettings.retry": "Повторить",
+  "ai.toolSettings.applyingHttp": "Применение настроек HTTP...",
 };

application/i18n/locales/ru/core.ts

@@ -134,7 +134,12 @@ export const ruCoreMessages: Messages = {
   'settings.system.clearTempFiles': 'Очистить временные файлы',
   'settings.system.clearing': 'Очистка...',
   'settings.system.clearResult': 'Удалено файлов: {deleted}, ошибок: {failed}.',
-  'settings.system.tempDirectoryHint': 'Временные файлы создаются при открытии удалённых файлов во внешних приложениях. Они автоматически очищаются при закрытии SFTP-сессий.',
+  'settings.system.tempDirChoose': 'Выбрать папку',
+  'settings.system.tempDirManual': 'Введите абсолютный путь к папке',
+  'settings.system.tempDirApply': 'Применить',
+  'settings.system.tempDirReset': 'Сбросить по умолчанию',
+  'settings.system.tempDirError': 'Не удалось использовать эту папку.',
+  'settings.system.tempDirectoryHint': 'Используется для промежуточного хранения SFTP-передач и файлов, открытых во внешних приложениях. Смена папки во время передачи может повлиять на эту передачу.',
   'settings.system.credentials.title': 'Защита учётных данных',
   'settings.system.credentials.status': 'Статус',
   'settings.system.credentials.checking': 'Проверка...',
@@ -1240,6 +1245,9 @@ export const ruCoreMessages: Messages = {
   "settings.plugins.openManager": "Открыть управление плагинами",
   "settings.plugins.sources.conflict": "This ID is installed from another source. Uninstall and explicitly reset its private data before switching. Existing source:",
   "settings.plugins.sources.clearPrivate": "Also clear this source’s private data, grants and secrets to reinstall from another source. This cannot be undone.",
+  "settings.plugins.sources.short.official": "Официальный",
+  "settings.plugins.sources.short.thirdparty": "Сторонний",
+  "settings.plugins.sources.short.local": "Локальный",
   "settings.plugins.sources.official": "Official marketplace",
   "settings.plugins.sources.thirdparty": "Third-party marketplace",
   "settings.plugins.sources.manage": "Manage sources",
@@ -1258,6 +1266,7 @@ export const ruCoreMessages: Messages = {
   "settings.plugins.sources.local": "Local import",
   "settings.plugins.sources.all": "All sources",
   "settings.plugins.title": "Плагины",
+  "settings.plugins.configuration": "Настройки плагина",
   "settings.plugins.description": "Управляйте плагинами и просматривайте каталог.",
   'settings.plugins.loading': 'Загрузка настроек плагинов…',
   'settings.plugins.empty': 'Включённые плагины не предоставляют настройки.',

application/i18n/locales/ru/monitor.ts

@@ -1,4 +1,8 @@
 export const ruMonitorMessages = {
+  "monitor.systemDisks": "Системные разделы ({count})",
+  "monitor.systemDisksAlert": "Использование системного раздела превышает 80 %; группа раскрыта автоматически.",
+  "monitor.diskIoTotal": "Всего",
+  "monitor.partitionIoHint": "Ввод-вывод блочного устройства точки монтирования. Точки одного устройства показывают одинаковые скорости. Недоступно до двух корректных замеров или без определённого устройства; macOS не поддерживается.",
   "monitor.diskIo": "Дисковый ввод-вывод",
   "monitor.diskRead": "Чтение",
   "monitor.diskWrite": "Запись",

application/i18n/locales/ru/terminal.ts

@@ -478,6 +478,7 @@ export const ruTerminalMessages: Messages = {
   'cloudSync.localBackups.clearFailed': 'Не удалось удалить все локальные копии. Повторите попытку.',
   'cloudSync.localBackups.title': 'История локальных резервных копий',
   'cloudSync.localBackups.desc': 'Netcatty сохраняет локальные точки восстановления перед сменой версии приложения и перед восстановлением хранилища.',
+  'cloudSync.localBackups.folderWarning': 'Эта папка сама по себе не является полной переносимой резервной копией. Удаление или очистка профиля приложения (userData) может сделать эти точки восстановления нечитаемыми.',
   'cloudSync.localBackups.retentionTitle': 'Хранение резервных копий',
   'cloudSync.localBackups.retentionDesc': 'Выберите, сколько локальных резервных копий должен хранить Netcatty.',
   'cloudSync.localBackups.maxCount': 'Макс. число копий',
@@ -492,6 +493,7 @@ export const ruTerminalMessages: Messages = {
   'cloudSync.localBackups.restoreSuccess': 'Локальная резервная копия восстановлена.',
   'cloudSync.localBackups.restoreFailedTitle': 'Ошибка восстановления',
   'cloudSync.localBackups.restoreMissing': 'Резервная копия не найдена.',
+  'cloudSync.localBackups.decryptFailed': 'Текущий профиль приложения не может расшифровать эту копию. Возможно, отсутствует ключ шифрования, профиль изменился или копия повреждена.',
   'cloudSync.localBackups.protectiveBackupFailed': 'Не удалось создать защитную резервную копию, поэтому восстановление было прервано для защиты ваших текущих данных. Устраните основную проблему (например, доступ к keychain) и попробуйте снова. Подробности: {message}',
   'cloudSync.localBackups.restoreConfirmTitle': 'Восстановить эту резервную копию?',
   'cloudSync.localBackups.restoreConfirmDesc': 'Ваши текущие хосты, ключи, сниппеты и настройки будут заменены содержимым этой резервной копии. Перед этим автоматически создаётся защитный снимок текущих данных.',

application/i18n/locales/zh-CN/ai.ts

@@ -525,6 +525,8 @@ export const zhCNAiMessages: Messages = {
   'ai.chat.alwaysAllow': '始终',
   'ai.chat.slashStopDesc': '停止当前 AI 回合并取消进行中的工具',
   'ai.chat.slashCompactDesc': '压缩较早的会话上下文',
+  'ai.chat.slashRenameDesc': '重命名当前聊天（/rename <标题>）',
+  'ai.chat.slashChatsDesc': '列出此面板可见的聊天',
   'ai.chat.reject': '拒绝',
   'ai.chat.toolLabel': '工具',
   'ai.chat.targetLabel': '目标',
@@ -587,6 +589,28 @@ export const zhCNAiMessages: Messages = {
   'ai.chat.recent': '最近',
   'ai.chat.viewAll': '查看全部',
   'ai.chat.untitled': '无标题',
+  'ai.chat.renameChat': '重命名聊天',
+  'ai.chat.renameUsage': '用法：/rename <新标题>',
+  'ai.chat.renameNoActive': '当前没有可重命名的聊天。',
+  'ai.chat.renameDone': '聊天已重命名为「{title}」。',
+  'ai.chat.exportSessions': '导出 AI 会话',
+  'ai.chat.importSessions': '导入 AI 会话',
+  'ai.chat.exportDone': 'AI 会话已导出到 {path}。',
+  'ai.chat.exportDoneNoPath': 'AI 会话已导出。',
+  'ai.chat.exportUnavailable': '当前环境不支持导出 AI 会话。',
+  'ai.chat.importDone': '已导入 {n} 个 AI 会话。',
+  'ai.chat.importNone': '所选文件中没有可导入的 AI 会话。',
+  'ai.chat.chatsHeader': '此面板可见的聊天：',
+  'ai.chat.chatsEmpty': '此面板没有可见的聊天。',
+  'ai.chat.chatsScopeWorkspace': '工作区',
+  'ai.chat.chatsScopeTerminal': '终端',
+  'ai.chat.chatsScopeGlobal': '全局',
+  'ai.chat.chatsScopeDangling': '已断开关联',
+  'ai.chat.slashRebindDesc': '将断联的聊天重绑到此面板（/rebind <序号>）',
+  'ai.chat.chatsRebindHint': '断联的聊天可用 /rebind <序号> 恢复。',
+  'ai.chat.rebindUsage': '用法：/rebind <序号>',
+  'ai.chat.rebindDone': '聊天“{title}”已重绑到此面板。',
+  'ai.chat.rebindUnavailable': '当前面板范围内没有可用的重绑目标。',
   'ai.chat.justNow': '刚刚',
   'ai.chat.minutesAgo': '{n}分钟前',
   'ai.chat.hoursAgo': '{n}小时前',
@@ -795,4 +819,27 @@ export const zhCNAiMessages: Messages = {
   'zmodem.overwrite.skip': '跳过',
   'zmodem.overwrite.cancel': '取消',
   'settings.shortcuts.resetToDefault': '重置为默认',
+  "ai.toolSettings.immediate": "更改立即生效，关闭此窗口不会撤销。",
+  "ai.toolSettings.privacyOn": "已启用文本脱敏",
+  "ai.toolSettings.privacyOff": "未启用文本脱敏",
+  "ai.toolSettings.ruleSummary": "{cidrs} 个附加 IP 范围 · {patterns} 条自定义规则",
+  "ai.toolSettings.configurePrivacy": "配置隐私",
+  "ai.toolSettings.unsaved": "有未保存的更改",
+  "ai.toolSettings.viewSkills": "查看 CLI 指引",
+  "ai.toolSettings.viewPrompt": "查看接入提示词",
+  "ai.toolSettings.behavior": "MCP 行为",
+  "ai.toolSettings.configureBehavior": "配置行为",
+  "ai.toolSettings.configureClients": "配置客户端",
+  "ai.toolSettings.httpOn": "HTTP 已启用",
+  "ai.toolSettings.httpOff": "HTTP 未启用",
+  "ai.toolSettings.loopback": "仅本地连接（127.0.0.1）",
+  "ai.toolSettings.configureHttp": "配置 HTTP",
+  "ai.toolSettings.hideSecret": "隐藏密钥",
+  "ai.toolSettings.showSecret": "显示密钥",
+  "ai.toolSettings.manualSetup": "手动配置",
+  "ai.toolSettings.format": "格式",
+  "ai.toolSettings.connectionDetails": "连接详情",
+  "ai.toolSettings.conflict": "设置已在另一窗口更改，当前草稿已保留。请取消并重新打开以加载已保存的设置。",
+  "ai.toolSettings.retry": "重试",
+  "ai.toolSettings.applyingHttp": "正在应用 HTTP 配置…",
 };

application/i18n/locales/zh-CN/core.ts

@@ -165,7 +165,12 @@ export const zhCNCoreMessages: Messages = {
   'settings.system.clearTempFiles': '清理临时文件',
   'settings.system.clearing': '清理中...',
   'settings.system.clearResult': '已删除 {deleted} 个文件，{failed} 个失败。',
-  'settings.system.tempDirectoryHint': '临时文件在使用外部应用打开远程文件时创建。SFTP 会话关闭时会自动清理。',
+  'settings.system.tempDirChoose': '选择文件夹',
+  'settings.system.tempDirManual': '输入绝对文件夹路径',
+  'settings.system.tempDirApply': '应用',
+  'settings.system.tempDirReset': '恢复默认',
+  'settings.system.tempDirError': '无法使用此文件夹。',
+  'settings.system.tempDirectoryHint': 'Netcatty 在所选文件夹中创建 Netcatty 临时子文件夹，用于 SFTP 传输暂存和外部编辑文件。传输期间更改文件夹可能影响该传输。',
   'settings.system.credentials.title': '凭据保护',
   'settings.system.credentials.status': '状态',
   'settings.system.credentials.checking': '检查中...',
@@ -1290,6 +1295,9 @@ Vaults 标签保持扁平，不使用这块背景。
   "settings.plugins.openManager": "打开插件管理",
   "settings.plugins.sources.conflict": "此 ID 已从其他来源安装。请先卸载并明确清理旧来源数据，再换源重装。原来源：",
   "settings.plugins.sources.clearPrivate": "同时清除本来源的私有数据、授权和秘密，以便显式换源重装。此操作不可撤销。",
+  "settings.plugins.sources.short.official": "官方",
+  "settings.plugins.sources.short.thirdparty": "第三方",
+  "settings.plugins.sources.short.local": "本地",
   "settings.plugins.sources.official": "官方市场",
   "settings.plugins.sources.thirdparty": "第三方市场",
   "settings.plugins.sources.manage": "管理来源",
@@ -1308,6 +1316,7 @@ Vaults 标签保持扁平，不使用这块背景。
   "settings.plugins.sources.local": "本地导入",
   "settings.plugins.sources.all": "全部来源",
   "settings.plugins.title": "插件",
+  "settings.plugins.configuration": "插件设置",
   "settings.plugins.description": "管理已安装插件，浏览精选目录。",
   'settings.plugins.loading': '正在加载插件设置…',
   'settings.plugins.empty': '当前没有已启用插件提供设置。',

application/i18n/locales/zh-CN/monitor.ts

@@ -1,4 +1,8 @@
 export const zhCNMonitorMessages = {
+  "monitor.systemDisks": "系统分区（{count}）",
+  "monitor.systemDisksAlert": "系统分区使用率超过 80%，已自动展开。",
+  "monitor.diskIoTotal": "汇总",
+  "monitor.partitionIoHint": "此挂载点对应块设备的读写速率；共用设备的挂载点显示相同速率。取得两次有效采样前或无法识别块设备时显示 --；暂不支持 macOS。",
   "monitor.diskIo": "磁盘 I/O",
   "monitor.diskRead": "读取",
   "monitor.diskWrite": "写入",

application/i18n/locales/zh-CN/vault.ts

@@ -888,6 +888,7 @@ export const zhCNVaultMessages: Messages = {
   'cloudSync.localBackups.clearFailed': '未能清空全部本地备份，请重试。',
   'cloudSync.localBackups.title': '本地备份历史',
   'cloudSync.localBackups.desc': 'Netcatty 会在版本变化前，以及恢复主机库前，自动留下一份本地恢复点。',
+  'cloudSync.localBackups.folderWarning': '仅复制此文件夹并不构成完整、可迁移的备份。删除或清空应用配置目录（userData）可能导致这些恢复点无法读取。',
   'cloudSync.localBackups.retentionTitle': '备份保留数量',
   'cloudSync.localBackups.retentionDesc': '设置 Netcatty 最多保留多少份本地备份。',
   'cloudSync.localBackups.maxCount': '最多保留',
@@ -902,6 +903,7 @@ export const zhCNVaultMessages: Messages = {
   'cloudSync.localBackups.restoreSuccess': '已恢复本地备份。',
   'cloudSync.localBackups.restoreFailedTitle': '恢复失败',
   'cloudSync.localBackups.restoreMissing': '找不到这份备份。',
+  'cloudSync.localBackups.decryptFailed': '当前应用配置无法解密此备份。可能是加密密钥丢失、应用配置已更改，或备份已损坏。',
   'cloudSync.localBackups.protectiveBackupFailed': '无法创建保护性备份，已中止恢复以避免覆盖当前数据。请先解决底层问题（例如钥匙串访问）后重试。详情：{message}',
   'cloudSync.localBackups.restoreConfirmTitle': '确认恢复此备份？',
   'cloudSync.localBackups.restoreConfirmDesc': '当前的主机、密钥、代码片段与设置将被替换为此备份中的内容。系统会先自动创建一个保护性快照，便于撤销。',

application/i18n/locales/zh-TW/ai.ts

@@ -515,6 +515,8 @@ export const zhTWAiMessages: Messages = {
   'ai.chat.alwaysAllow': '始終',
   'ai.chat.slashStopDesc': '停止目前 AI 回合並取消進行中的工具',
   'ai.chat.slashCompactDesc': '壓縮較早的對話上下文',
+  'ai.chat.slashRenameDesc': '重新命名目前聊天（/rename <標題>）',
+  'ai.chat.slashChatsDesc': '列出此面板可見的聊天',
   'ai.chat.reject': '拒絕',
   'ai.chat.toolLabel': '工具',
   'ai.chat.targetLabel': '目標',
@@ -577,6 +579,28 @@ export const zhTWAiMessages: Messages = {
   'ai.chat.recent': '最近',
   'ai.chat.viewAll': '檢視全部',
   'ai.chat.untitled': '無標題',
+  'ai.chat.renameChat': '重新命名聊天',
+  'ai.chat.renameUsage': '用法：/rename <新標題>',
+  'ai.chat.renameNoActive': '目前沒有可重新命名的聊天。',
+  'ai.chat.renameDone': '聊天已重新命名為「{title}」。',
+  'ai.chat.exportSessions': '匯出 AI 會話',
+  'ai.chat.importSessions': '匯入 AI 會話',
+  'ai.chat.exportDone': 'AI 會話已匯出到 {path}。',
+  'ai.chat.exportDoneNoPath': 'AI 會話已匯出。',
+  'ai.chat.exportUnavailable': '目前環境不支援匯出 AI 會話。',
+  'ai.chat.importDone': '已匯入 {n} 個 AI 會話。',
+  'ai.chat.importNone': '所選檔案中沒有可匯入的 AI 會話。',
+  'ai.chat.chatsHeader': '此面板可見的聊天：',
+  'ai.chat.chatsEmpty': '此面板沒有可見的聊天。',
+  'ai.chat.chatsScopeWorkspace': '工作區',
+  'ai.chat.chatsScopeTerminal': '終端',
+  'ai.chat.chatsScopeGlobal': '全域',
+  'ai.chat.chatsScopeDangling': '已斷開關聯',
+  'ai.chat.slashRebindDesc': '將斷開關聯的聊天重新綁定到此面板（/rebind <序號>）',
+  'ai.chat.chatsRebindHint': '斷開關聯的聊天可用 /rebind <序號> 恢復。',
+  'ai.chat.rebindUsage': '用法：/rebind <序號>',
+  'ai.chat.rebindDone': '聊天「{title}」已重新綁定到此面板。',
+  'ai.chat.rebindUnavailable': '目前面板範圍內沒有可用的重新綁定目標。',
   'ai.chat.justNow': '剛剛',
   'ai.chat.minutesAgo': '{n}分鐘前',
   'ai.chat.hoursAgo': '{n}小時前',
@@ -785,4 +809,27 @@ export const zhTWAiMessages: Messages = {
   'zmodem.overwrite.skip': '跳過',
   'zmodem.overwrite.cancel': '取消',
   'settings.shortcuts.resetToDefault': '重設為預設值',
+  "ai.toolSettings.immediate": "變更立即生效，關閉此視窗不會復原。",
+  "ai.toolSettings.privacyOn": "已啟用文字遮蔽",
+  "ai.toolSettings.privacyOff": "未啟用文字遮蔽",
+  "ai.toolSettings.ruleSummary": "{cidrs} 個額外 IP 範圍 · {patterns} 條自訂規則",
+  "ai.toolSettings.configurePrivacy": "設定隱私",
+  "ai.toolSettings.unsaved": "有未儲存的變更",
+  "ai.toolSettings.viewSkills": "查看 CLI 指引",
+  "ai.toolSettings.viewPrompt": "查看接入提示詞",
+  "ai.toolSettings.behavior": "MCP 行為",
+  "ai.toolSettings.configureBehavior": "設定行為",
+  "ai.toolSettings.configureClients": "設定用戶端",
+  "ai.toolSettings.httpOn": "HTTP 已啟用",
+  "ai.toolSettings.httpOff": "HTTP 未啟用",
+  "ai.toolSettings.loopback": "僅本機連線（127.0.0.1）",
+  "ai.toolSettings.configureHttp": "設定 HTTP",
+  "ai.toolSettings.hideSecret": "隱藏金鑰",
+  "ai.toolSettings.showSecret": "顯示金鑰",
+  "ai.toolSettings.manualSetup": "手動設定",
+  "ai.toolSettings.format": "格式",
+  "ai.toolSettings.connectionDetails": "連線詳情",
+  "ai.toolSettings.conflict": "設定已在其他視窗變更，目前草稿已保留。請取消並重新開啟以載入已儲存的設定。",
+  "ai.toolSettings.retry": "重試",
+  "ai.toolSettings.applyingHttp": "正在套用 HTTP 設定…",
 };

application/i18n/locales/zh-TW/core.ts

@@ -167,7 +167,12 @@ export const zhTWCoreMessages: Messages = {
   'settings.system.clearTempFiles': '清理臨時檔案',
   'settings.system.clearing': '清理中...',
   'settings.system.clearResult': '已刪除 {deleted} 個檔案，{failed} 個失敗。',
-  'settings.system.tempDirectoryHint': '臨時檔案在使用外部應用程式開啟遠端檔案時建立。SFTP 工作階段關閉時會自動清理。',
+  'settings.system.tempDirChoose': '選擇資料夾',
+  'settings.system.tempDirManual': '輸入絕對資料夾路徑',
+  'settings.system.tempDirApply': '套用',
+  'settings.system.tempDirReset': '恢復預設',
+  'settings.system.tempDirError': '無法使用此資料夾。',
+  'settings.system.tempDirectoryHint': '用於 SFTP 傳輸暫存與外部編輯檔案。傳輸期間變更資料夾可能影響該傳輸。',
   'settings.system.credentials.title': '憑證保護',
   'settings.system.credentials.status': '狀態',
   'settings.system.credentials.checking': '檢查中...',
@@ -1261,6 +1266,9 @@ Vaults 分頁維持扁平，不使用這塊背景。
   "settings.plugins.openManager": "開啟插件管理",
   "settings.plugins.sources.conflict": "此 ID 已从其他来源安装。请先卸载并明确清理旧来源数据，再换源重装。原来源：",
   "settings.plugins.sources.clearPrivate": "同时清除本来源的私有数据、授权和秘密，以便显式换源重装。此操作不可撤销。",
+  "settings.plugins.sources.short.official": "官方",
+  "settings.plugins.sources.short.thirdparty": "第三方",
+  "settings.plugins.sources.short.local": "本機",
   "settings.plugins.sources.official": "官方市场",
   "settings.plugins.sources.thirdparty": "第三方市场",
   "settings.plugins.sources.manage": "管理来源",
@@ -1279,6 +1287,7 @@ Vaults 分頁維持扁平，不使用這塊背景。
   "settings.plugins.sources.local": "本地导入",
   "settings.plugins.sources.all": "全部来源",
   "settings.plugins.title": "插件",
+  "settings.plugins.configuration": "插件設定",
   "settings.plugins.description": "管理已安裝插件，瀏覽精選目錄。",
   'settings.plugins.loading': '正在載入外掛程式設定…',
   "settings.plugins.market.results": "{count} 個插件",

application/i18n/locales/zh-TW/monitor.ts

@@ -1,4 +1,8 @@
 export const zhTWMonitorMessages = {
+  "monitor.systemDisks": "系統分割區（{count}）",
+  "monitor.systemDisksAlert": "系統分割區使用率超過 80%，已自動展開。",
+  "monitor.diskIoTotal": "彙總",
+  "monitor.partitionIoHint": "此掛載點對應區塊裝置的讀寫速率；共用裝置的掛載點顯示相同速率。取得兩次有效取樣前或無法識別區塊裝置時顯示 --；暫不支援 macOS。",
   "monitor.diskIo": "磁碟 I/O",
   "monitor.diskRead": "讀取",
   "monitor.diskWrite": "寫入",

application/i18n/locales/zh-TW/vault.ts

@@ -888,6 +888,7 @@ export const zhTWVaultMessages: Messages = {
   'cloudSync.localBackups.clearFailed': '未能清空全部本機備份，請重試。',
   'cloudSync.localBackups.title': '本機備份歷史',
   'cloudSync.localBackups.desc': 'Netcatty 會在版本變化前，以及恢復主機庫前，自動留下一份本機恢復點。',
+  'cloudSync.localBackups.folderWarning': '僅複製此資料夾並不構成完整、可攜的備份。刪除或清空應用程式設定目錄（userData）可能導致這些還原點無法讀取。',
   'cloudSync.localBackups.retentionTitle': '備份保留數量',
   'cloudSync.localBackups.retentionDesc': '設定 Netcatty 最多保留多少份本機備份。',
   'cloudSync.localBackups.maxCount': '最多保留',
@@ -902,6 +903,7 @@ export const zhTWVaultMessages: Messages = {
   'cloudSync.localBackups.restoreSuccess': '已恢復本機備份。',
   'cloudSync.localBackups.restoreFailedTitle': '恢復失敗',
   'cloudSync.localBackups.restoreMissing': '找不到這份備份。',
+  'cloudSync.localBackups.decryptFailed': '目前的應用程式設定無法解密此備份。可能是加密金鑰遺失、應用程式設定已變更，或備份已損毀。',
   'cloudSync.localBackups.protectiveBackupFailed': '無法建立保護性備份，已中止恢復以避免覆蓋目前資料。請先解決底層問題（例如鑰匙串存取）後重試。詳情：{message}',
   'cloudSync.localBackups.restoreConfirmTitle': '確認恢復此備份？',
   'cloudSync.localBackups.restoreConfirmDesc': '目前的主機、金鑰、程式碼片段與設定將被替換為此備份中的內容。系統會先自動建立一個保護性快照，便於復原。',

application/i18n/messages.ts

@@ -1,17 +1,78 @@
 import en, { type Messages } from './locales/en';
-import zhCN from './locales/zh-CN';
-import zhTW from './locales/zh-TW';
-import ru from './locales/ru';
-import es from './locales/es';
 
-// Keep keys stable; add new locales by adding another import and map entry.
+// Keep keys stable; add new locales by adding a loader below and an entry in
+// SUPPORTED_UI_LOCALES (infrastructure/config/i18n.ts).
 export { type Messages };
 
-export const MESSAGES_BY_LOCALE: Record<string, Messages> = {
-  en,
-  ru,
-  es,
-  'zh-CN': zhCN,
-  'zh-TW': zhTW,
+/**
+ * Lookup order for the "same base language" fallback in I18nProvider (for
+ * example zh-TW falls back to zh-CN, the first `zh*` entry). Matches the key
+ * order of the old static MESSAGES_BY_LOCALE map.
+ */
+export const LOCALE_MESSAGE_KEYS = ['en', 'ru', 'es', 'zh-CN', 'zh-TW'] as const;
+
+/**
+ * Only English is bundled with the startup chunk; other locales are loaded on
+ * demand. All five dictionaries used to be parsed by every window at startup
+ * (~1.3 MB of the entry chunk) even though one locale is in use.
+ */
+const LOCALE_LOADERS: Record<string, () => Promise<{ default: Messages }>> = {
+  ru: () => import('./locales/ru'),
+  es: () => import('./locales/es'),
+  'zh-CN': () => import('./locales/zh-CN'),
+  'zh-TW': () => import('./locales/zh-TW'),
 };
 
+const loadedMessages: Record<string, Messages> = { en };
+const pendingLoads = new Map<string, Promise<void>>();
+const listeners = new Set<() => void>();
+let messagesVersion = 0;
+
+export function getLoadedLocaleMessages(locale: string): Messages | undefined {
+  return loadedMessages[locale];
+}
+
+export function getLocaleMessagesVersion(): number {
+  return messagesVersion;
+}
+
+export function subscribeLocaleMessages(listener: () => void): () => void {
+  listeners.add(listener);
+  return () => {
+    listeners.delete(listener);
+  };
+}
+
+/** The same-base fallback locale that I18nProvider consults for `locale`. */
+export function getBaseFallbackLocale(locale: string): string | undefined {
+  const base = locale.split('-')[0];
+  return LOCALE_MESSAGE_KEYS.find((key) => key === base || key.startsWith(`${base}-`));
+}
+
+function loadOne(locale: string): Promise<void> {
+  if (loadedMessages[locale]) return Promise.resolve();
+  const loader = LOCALE_LOADERS[locale];
+  if (!loader) return Promise.resolve();
+  let pending = pendingLoads.get(locale);
+  if (!pending) {
+    pending = loader()
+      .then((module) => {
+        loadedMessages[locale] = module.default;
+        messagesVersion += 1;
+        for (const listener of listeners) listener();
+      })
+      .finally(() => {
+        pendingLoads.delete(locale);
+      });
+    pendingLoads.set(locale, pending);
+  }
+  return pending;
+}
+
+/** Load the dictionaries `locale` resolves through (itself and its base fallback). */
+export function loadLocaleMessages(locale: string): Promise<void> {
+  const needed = new Set([locale]);
+  const fallback = getBaseFallbackLocale(locale);
+  if (fallback) needed.add(fallback);
+  return Promise.all([...needed].map(loadOne)).then(() => undefined);
+}

application/state/agentSessionReconnect.test.ts

@@ -0,0 +1,20 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { requestAgentSessionReconnect } from './agentSessionReconnect';
+
+test('reconnect preserves identity and only dispatches disconnected eligible sessions', () => {
+  let calls = 0;
+  const registry = { isActive: () => false, requestIfAvailable: () => { calls++; return true; } };
+  assert.equal(requestAgentSessionReconnect('s', undefined, registry).ok, false);
+  assert.equal(requestAgentSessionReconnect('s', 'connected', registry).status, 'connected');
+  assert.equal(requestAgentSessionReconnect('s', 'connecting', registry).started, false);
+  const result = requestAgentSessionReconnect('s', 'disconnected', registry);
+  assert.deepEqual(result, { ok: true, started: true, sessionId: 's', status: 'reconnecting', shellReady: false });
+  assert.equal(calls, 1);
+});
+
+test('auto/manual reconnect and unavailable terminal cannot queue another recovery', () => {
+  const registry = { isActive: () => true, requestIfAvailable: () => { throw Error('must not dispatch'); } };
+  assert.equal(requestAgentSessionReconnect('s', 'disconnected', registry).started, false);
+  assert.equal(requestAgentSessionReconnect('s', 'disconnected', { isActive: () => false, requestIfAvailable: () => false }).code, 'RECONNECT_UNAVAILABLE');
+});

application/state/agentSessionReconnect.ts

@@ -0,0 +1,21 @@
+type ReconnectRegistry = {
+  isActive: (sessionId: string) => boolean;
+  requestIfAvailable: (sessionId: string) => boolean;
+};
+
+/** Synchronous dispatch only: no queued recovery after scope/terminal disposal. */
+export function requestAgentSessionReconnect(
+  sessionId: string,
+  status: string | undefined,
+  registry: ReconnectRegistry,
+): Record<string, unknown> {
+  if (!status) return { ok: false, started: false, error: `Session "${sessionId}" was not found.` };
+  if (status === 'connected') return { ok: true, started: false, sessionId, status: 'connected', shellReady: false };
+  if (status === 'connecting' || registry.isActive(sessionId)) {
+    return { ok: true, started: false, sessionId, status: 'reconnecting' };
+  }
+  if (status !== 'disconnected' || !registry.requestIfAvailable(sessionId)) {
+    return { ok: false, started: false, sessionId, code: 'RECONNECT_UNAVAILABLE', error: 'Reconnect is unavailable: terminal may be unmounted, waiting for authentication, or recovering. Inspect session state and the Netcatty UI.' };
+  }
+  return { ok: true, started: true, sessionId, status: 'reconnecting', shellReady: false };
+}

application/state/aiScopeCleanup.test.ts

@@ -2,14 +2,9 @@ import test from "node:test";
 import assert from "node:assert/strict";
 
 import type {
-  AIPanelView,
   AISession,
 } from "../../infrastructure/ai/types.ts";
-import { createEmptyDraft } from "./aiDraftState.ts";
-import {
-  pruneInactiveScopedSessions,
-  pruneInactiveScopedTransientState,
-} from "./aiScopeCleanup.ts";
+import { pruneInactiveScopedSessions } from "./aiScopeCleanup.ts";
 
 function createSession(id: string, scope: AISession["scope"], externalSessionId?: string): AISession {
   return {
@@ -24,47 +19,6 @@ function createSession(id: string, scope: AISession["scope"], externalSessionId?
   };
 }
 
-test("pruneInactiveScopedTransientState removes closed workspace and terminal scope state", () => {
-  const activeSessionIdMap = {
-    "terminal:open-terminal": "session-open",
-    "terminal:closed-terminal": "session-closed-terminal",
-    "workspace:open-workspace": "session-open-workspace",
-    "workspace:closed-workspace": "session-closed-workspace",
-  };
-  const draftsByScope = {
-    "terminal:open-terminal": createEmptyDraft("catty"),
-    "terminal:closed-terminal": createEmptyDraft("catty"),
-    "workspace:open-workspace": createEmptyDraft("catty"),
-    "workspace:closed-workspace": createEmptyDraft("catty"),
-  };
-  const panelViewByScope = {
-    "terminal:open-terminal": { mode: "draft" },
-    "terminal:closed-terminal": { mode: "session", sessionId: "session-closed-terminal" },
-    "workspace:open-workspace": { mode: "draft" },
-    "workspace:closed-workspace": { mode: "session", sessionId: "session-closed-workspace" },
-  } satisfies Record<string, AIPanelView>;
-
-  const next = pruneInactiveScopedTransientState(
-    activeSessionIdMap,
-    draftsByScope,
-    panelViewByScope,
-    new Set(["open-terminal", "open-workspace"]),
-  );
-
-  assert.deepEqual(next.activeSessionIdMap, {
-    "terminal:open-terminal": "session-open",
-    "workspace:open-workspace": "session-open-workspace",
-  });
-  assert.deepEqual(next.draftsByScope, {
-    "terminal:open-terminal": draftsByScope["terminal:open-terminal"],
-    "workspace:open-workspace": draftsByScope["workspace:open-workspace"],
-  });
-  assert.deepEqual(next.panelViewByScope, {
-    "terminal:open-terminal": panelViewByScope["terminal:open-terminal"],
-    "workspace:open-workspace": panelViewByScope["workspace:open-workspace"],
-  });
-});
-
 test("pruneInactiveScopedSessions reports inactive targets without deleting persisted history", () => {
   const sessions = [
     createSession("terminal-restorable", {

application/state/aiScopeCleanup.ts

@@ -6,7 +6,6 @@ import type {
 
 type DraftsByScope = Partial<Record<string, AIDraft>>;
 type PanelViewByScope = Partial<Record<string, AIPanelView>>;
-type ActiveSessionIdMap = Record<string, string | null>;
 
 function isInactiveScopedTarget(
   scopeKey: string,
@@ -55,41 +54,6 @@ export function pruneInactiveScopedState(
   };
 }
 
-export function pruneInactiveScopedTransientState(
-  activeSessionIdMap: ActiveSessionIdMap,
-  draftsByScope: DraftsByScope,
-  panelViewByScope: PanelViewByScope,
-  activeTargetIds: Set<string>,
-): {
-  activeSessionIdMap: ActiveSessionIdMap;
-  draftsByScope: DraftsByScope;
-  panelViewByScope: PanelViewByScope;
-} {
-  let activeSessionMapChanged = false;
-  const nextActiveSessionIdMap: ActiveSessionIdMap = {};
-
-  for (const [scopeKey, sessionId] of Object.entries(activeSessionIdMap)) {
-    if (isInactiveScopedTarget(scopeKey, activeTargetIds)) {
-      activeSessionMapChanged = true;
-      continue;
-    }
-
-    nextActiveSessionIdMap[scopeKey] = sessionId;
-  }
-
-  const nextScopedState = pruneInactiveScopedState(
-    draftsByScope,
-    panelViewByScope,
-    activeTargetIds,
-  );
-
-  return {
-    activeSessionIdMap: activeSessionMapChanged ? nextActiveSessionIdMap : activeSessionIdMap,
-    draftsByScope: nextScopedState.draftsByScope,
-    panelViewByScope: nextScopedState.panelViewByScope,
-  };
-}
-
 export function pruneInactiveScopedSessions(
   sessions: AISession[],
   activeTargetIds: Set<string>,

application/state/aiSessionsBackup.test.ts

@@ -0,0 +1,147 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+
+import type { AISession } from '../../infrastructure/ai/types';
+import {
+  DebouncedBackupMirror,
+  isMissingOrCorruptSessionsStore,
+  mergeImportedSessions,
+  parseBackupSessions,
+  readLiveSessionsArray,
+  shouldRestoreFromBackup,
+} from './aiSessionsBackup';
+import { prepareRestoredSessions, pruneSessionsForStorage } from './aiStateSnapshots';
+
+function makeSession(id: string, updatedAt = 1_000): AISession {
+  return {
+    id,
+    title: id,
+    agentId: 'catty',
+    scope: { type: 'workspace', targetId: 'ws-1' },
+    messages: [],
+    createdAt: updatedAt,
+    updatedAt,
+  } as never;
+}
+
+test('isMissingOrCorruptSessionsStore distinguishes missing or corrupt stores from valid arrays', () => {
+  assert.equal(isMissingOrCorruptSessionsStore(null), true);
+  assert.equal(isMissingOrCorruptSessionsStore(''), true);
+  assert.equal(isMissingOrCorruptSessionsStore('[]'), false);
+  assert.equal(isMissingOrCorruptSessionsStore('{corrupt'), true);
+  assert.equal(isMissingOrCorruptSessionsStore('{}'), true);
+  assert.equal(isMissingOrCorruptSessionsStore('[{"id":"s1"}]'), false);
+});
+
+test('readLiveSessionsArray normalizes missing and corrupt stores', () => {
+  for (const raw of [null, undefined, '', '{}', 'not-json']) {
+    assert.deepEqual(readLiveSessionsArray(raw), []);
+  }
+  const sessions = [makeSession('s1')];
+  assert.deepEqual(readLiveSessionsArray(JSON.stringify(sessions)), sessions);
+});
+
+test('parseBackupSessions ignores corrupt payloads and drops malformed entries', () => {
+  assert.equal(parseBackupSessions(null), null);
+  assert.equal(parseBackupSessions(''), null);
+  assert.equal(parseBackupSessions('not json'), null);
+  assert.equal(parseBackupSessions('{"id":"s1"}'), null);
+  assert.equal(parseBackupSessions(JSON.stringify([{ id: 's1' }])), null);
+  const sessions = parseBackupSessions(JSON.stringify([
+    { id: 's1' },
+    { nope: true },
+    { id: 'missing-scope', title: 'Missing scope', agentId: 'catty', messages: [], updatedAt: 1000 },
+    { ...makeSession('null-scope'), scope: null },
+    { ...makeSession('missing-title'), title: undefined },
+    { ...makeSession('missing-agent'), agentId: undefined },
+    { ...makeSession('null-message'), messages: [null] },
+    { ...makeSession('incomplete-message'), messages: [{ id: 'm' }] },
+    { ...makeSession('missing-content'), messages: [{ id: 'm', role: 'user', timestamp: 1000 }] },
+    { ...makeSession('invalid-content'), messages: [{ id: 'm', role: 'user', timestamp: 1000, content: null }] },
+    { ...makeSession('invalid-timestamp'), messages: [{ id: 'm', role: 'user', timestamp: null, content: 'hello' }] },
+    null,
+    { ...makeSession('s2'), messages: [{ id: 'm', role: 'user', timestamp: 1000, content: 'hello' }] },
+  ]));
+  assert.deepEqual(sessions?.map((session) => session.id), ['s2']);
+});
+
+test('restore preserves all sessions when cloud sync is enabled', () => {
+  const sessions = Array.from({ length: 51 }, (_, index) => makeSession(`s${index}`, index));
+  assert.deepEqual(prepareRestoredSessions(sessions, true), sessions);
+  const local = prepareRestoredSessions(sessions, false);
+  assert.equal(local.length, 50);
+  assert.equal(local.some(session => session.id === 's0'), false);
+});
+
+test('malformed imports cannot reach pruning or inject broken sessions', () => {
+  const current = [makeSession('live')];
+  const malformed = parseBackupSessions(JSON.stringify([{ id: 's1' }]));
+  assert.deepEqual(mergeImportedSessions(current, pruneSessionsForStorage(malformed ?? [])), current);
+  const valid = parseBackupSessions(JSON.stringify([{ id: 's1' }, makeSession('valid')]));
+  const merged = mergeImportedSessions(current, pruneSessionsForStorage(valid ?? []));
+  assert.deepEqual(new Set(merged.map((session) => session.id)), new Set(['live', 'valid']));
+});
+
+test('restore happens only on a missing or corrupt live store with a non-empty backup', () => {
+  const backup = JSON.stringify([makeSession('s1')]);
+  // Empty (or wiped) store -> restore.
+  assert.equal(shouldRestoreFromBackup(null, backup), true);
+  assert.equal(shouldRestoreFromBackup('', backup), true);
+  assert.equal(shouldRestoreFromBackup('[]', backup), false);
+  assert.equal(shouldRestoreFromBackup('{corrupt', backup), true);
+  // Non-empty live store -> never restore (explicit deletions must win).
+  assert.equal(shouldRestoreFromBackup('[{"id":"live"}]', backup), false);
+  // Empty/corrupt backup -> nothing to restore.
+  assert.equal(shouldRestoreFromBackup(null, null), false);
+  assert.equal(shouldRestoreFromBackup(null, '[]'), false);
+  assert.equal(shouldRestoreFromBackup(null, '{corrupt'), false);
+});
+
+test('mergeImportedSessions keys by id with the newer updatedAt winning', () => {
+  const current = [makeSession('keep', 100), makeSession('older', 100)];
+  const imported = [makeSession('newer', 200), makeSession('older', 50), makeSession('added', 1)];
+  const merged = mergeImportedSessions(current, imported);
+  const byId = new Map(merged.map((session) => [session.id, session]));
+  assert.equal(byId.get('older')?.updatedAt, 100);
+  assert.equal(byId.get('newer')?.updatedAt, 200);
+  assert.equal(byId.has('added'), true);
+  assert.equal(byId.has('keep'), true);
+  // Sorted newest-first for stable history ordering.
+  assert.deepEqual(
+    merged.map((session) => session.updatedAt),
+    [...merged.map((session) => session.updatedAt)].sort((a, b) => b - a),
+  );
+});
+
+test('DebouncedBackupMirror writes once per batch with the last payload', async () => {
+  const writes: string[] = [];
+  const mirror = new DebouncedBackupMirror((json) => writes.push(json), 15);
+  mirror.schedule('{"gen":1}');
+  mirror.schedule('{"gen":2}');
+  await new Promise((resolve) => setTimeout(resolve, 30));
+  mirror.schedule('{"gen":3}');
+  mirror.schedule('{"gen":4}');
+  await new Promise((resolve) => setTimeout(resolve, 40));
+  assert.deepEqual(writes, ['{"gen":2}', '{"gen":4}']);
+});
+
+test('DebouncedBackupMirror flushNow writes the pending payload immediately', () => {
+  const writes: string[] = [];
+  const mirror = new DebouncedBackupMirror((json) => writes.push(json), 60_000);
+  mirror.schedule('{"gen":1}');
+  mirror.flushNow();
+  assert.deepEqual(writes, ['{"gen":1}']);
+  // A second flush with nothing pending is a no-op.
+  mirror.flushNow();
+  assert.deepEqual(writes, ['{"gen":1}']);
+});
+
+test('readLiveSessionsArray treats non-array JSON as empty (corrupt)', () => {
+  assert.deepEqual(readLiveSessionsArray(null), []);
+  assert.deepEqual(readLiveSessionsArray(''), []);
+  assert.deepEqual(readLiveSessionsArray('{}'), []);
+  assert.deepEqual(readLiveSessionsArray('{"sessions":[]}'), []);
+  assert.deepEqual(readLiveSessionsArray('not-json'), []);
+  assert.deepEqual(readLiveSessionsArray('[]'), []);
+  assert.equal(readLiveSessionsArray('[{"id":"a"}]').length, 1);
+});

application/state/aiSessionsBackup.ts

@@ -0,0 +1,162 @@
+import type { AISession } from '../../infrastructure/ai/types';
+
+/**
+ * Renderer-side logic for the AI session durability layer (issue #4015 R2
+ * follow-up): a disk mirror of the localStorage session store plus a
+ * restore-on-empty-store boot path. The IPC plumbing lives in
+ * `electron/bridges/aiSessionsBackupBridge.cjs`; this module keeps the
+ * decisions pure so they can be tested without Electron.
+ */
+
+/** Debounce window: at most one backup write per mutation burst (~2s). */
+export const AI_SESSIONS_BACKUP_DEBOUNCE_MS = 2000;
+
+export interface AiSessionsBackupBridge {
+  aiSessionsBackupWrite?: (payload: { json: string }) => Promise<{ ok: boolean }>;
+  aiSessionsBackupReadLatest?: () => Promise<{ ok: boolean; json?: string }>;
+  aiSessionsBackupExport?: (payload: { json: string }) => Promise<{ success: boolean; filePath?: string }>;
+  aiSessionsBackupImport?: () => Promise<{ success: boolean; json?: string }>;
+}
+
+/**
+ * Parse the live sessions store once, returning both whether it is usable and
+ * its sessions. The history is often several MB; the helpers below used to
+ * parse it twice per call, and mount ran them back to back (five parses).
+ */
+export function parseSessionsStore(raw: string | null | undefined): { valid: boolean; sessions: AISession[] } {
+  if (raw == null || raw === '') return { valid: false, sessions: [] };
+  try {
+    const parsed = JSON.parse(raw);
+    return Array.isArray(parsed)
+      ? { valid: true, sessions: parsed as AISession[] }
+      : { valid: false, sessions: [] };
+  } catch {
+    return { valid: false, sessions: [] };
+  }
+}
+
+/** Restore only when the live store is missing or malformed. A valid empty
+ * array represents an intentional deletion and must remain authoritative. */
+export function isMissingOrCorruptSessionsStore(raw: string | null | undefined): boolean {
+  return !parseSessionsStore(raw).valid;
+}
+
+/** Read the live sessions array from a raw localStorage string. Returns [] when
+ * missing/corrupt (including parseable non-arrays such as `{}`), so callers never
+ * treat a non-array as AISession[]. */
+export function readLiveSessionsArray(raw: string | null | undefined): AISession[] {
+  return parseSessionsStore(raw).sessions;
+}
+
+/**
+ * Parse a backup payload into sessions. Returns null when the payload is
+ * corrupt or malformed (ignored gracefully); also drops entries without a
+ * usable required fields. Backup generations are written by the same serializer as the
+ * live store, so entries are expected to be full AISession objects.
+ */
+
+export function parseBackupSessions(json: string | null | undefined): AISession[] | null {
+  if (typeof json !== 'string' || json === '') return null;
+  let parsed: unknown;
+  try {
+    parsed = JSON.parse(json);
+  } catch {
+    return null;
+  }
+  if (!Array.isArray(parsed)) return null;
+  const sessions = parsed.filter(
+    (entry): entry is AISession => (
+      typeof entry === 'object' && entry !== null
+      && typeof (entry as AISession).id === 'string'
+      && typeof (entry as AISession).title === 'string'
+      && typeof (entry as AISession).agentId === 'string'
+      && typeof (entry as AISession).scope === 'object'
+      && (entry as AISession).scope !== null
+      && typeof (entry as AISession).scope.type === 'string'
+      && Array.isArray((entry as AISession).messages)
+      && (entry as AISession).messages.every(message => (
+        typeof message === 'object' && message !== null
+        && typeof message.id === 'string'
+        && typeof message.role === 'string'
+        && typeof message.content === 'string'
+        && typeof message.timestamp === 'number'
+        && Number.isFinite(message.timestamp)
+      ))
+      && typeof (entry as AISession).updatedAt === 'number'
+      && Number.isFinite((entry as AISession).updatedAt)
+    ),
+  );
+  return sessions.length > 0 ? sessions : null;
+}
+
+/**
+ * Decide whether to restore on boot: only when the live store is missing or corrupt AND
+ * the backup actually contains at least one session.
+ */
+export function shouldRestoreFromBackup(
+  liveRaw: string | null | undefined,
+  backupJson: string | null | undefined,
+): boolean {
+  if (!isMissingOrCorruptSessionsStore(liveRaw)) return false;
+  const sessions = parseBackupSessions(backupJson);
+  return sessions != null && sessions.length > 0;
+}
+
+/**
+ * Merge an imported backup into the current store: entries are keyed by id
+ * and the newer `updatedAt` wins. Explicit user action, so it may overwrite
+ * the live store (unlike the boot restore, which is empty-only).
+ */
+export function mergeImportedSessions(current: AISession[], imported: AISession[]): AISession[] {
+  const byId = new Map<string, AISession>();
+  for (const session of current) byId.set(session.id, session);
+  for (const session of imported) {
+    const existing = byId.get(session.id);
+    if (!existing || (session.updatedAt ?? 0) >= (existing.updatedAt ?? 0)) {
+      byId.set(session.id, session);
+    }
+  }
+  return Array.from(byId.values()).sort((a, b) => (b.updatedAt ?? 0) - (a.updatedAt ?? 0));
+}
+
+/**
+ * Debounced mirror scheduler. One rolling timer per process: the last
+ * mutation batch wins, and the write happens `debounceMs` after the batch
+ * settles (at most once per batch, per the durability spec).
+ */
+export class DebouncedBackupMirror {
+  private timer: ReturnType<typeof setTimeout> | null = null;
+  private pendingJson: string | null = null;
+
+  constructor(
+    private readonly write: (json: string) => void,
+    private readonly debounceMs: number = AI_SESSIONS_BACKUP_DEBOUNCE_MS,
+  ) {}
+
+  schedule(json: string) {
+    this.pendingJson = json;
+    if (this.timer) clearTimeout(this.timer);
+    this.timer = setTimeout(() => {
+      this.timer = null;
+      const json = this.pendingJson;
+      this.pendingJson = null;
+      if (json != null) this.write(json);
+    }, this.debounceMs);
+  }
+
+  flushNow() {
+    if (this.timer) {
+      clearTimeout(this.timer);
+      this.timer = null;
+    }
+    const json = this.pendingJson;
+    this.pendingJson = null;
+    if (json != null) this.write(json);
+  }
+
+  reset() {
+    if (this.timer) clearTimeout(this.timer);
+    this.timer = null;
+    this.pendingJson = null;
+  }
+}

application/state/aiStateSnapshots.test.ts

@@ -1,10 +1,16 @@
 import assert from 'node:assert/strict';
-import test from 'node:test';
+import test, { type TestContext } from 'node:test';
 import { createAiPrivacyService } from '../../electron/shared/aiPrivacyService.cjs';
 import {
   hasReversibleModelPrivacy,
   setReversibleModelPrivacy,
 } from '../../infrastructure/ai/harness/modelSecretRedaction';
+import {
+  STORAGE_KEY_AI_SESSIONS,
+  STORAGE_KEY_AI_SESSIONS_OVERFLOW,
+  STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW,
+  STORAGE_KEY_CLOUD_SYNC_AI_SESSIONS,
+} from '../../infrastructure/config/storageKeys';
 import type { AISession } from '../../infrastructure/ai/types';
 import { localStorageAdapter } from '../../infrastructure/persistence/localStorageAdapter';
 import {
@@ -16,6 +22,12 @@ import {
   latestAISessionsSnapshot,
   setLatestAIActiveSessionMapSnapshot,
   setLatestAISessionsSnapshot,
+  rebindActiveSessionMap,
+  readSessionsFromStorage,
+  prewarmAIStateStorageSnapshots,
+  writeSessionsForStorage,
+  flushBackupMirror,
+  __resetBackupMirrorForTests,
 } from './aiStateSnapshots';
 
 test('orphan cleanup keeps durable Catty output while explicit deletion removes it', async () => {
@@ -72,6 +84,424 @@ function makeSession(id: string, updatedAt: number, messages: unknown[]): AISess
   } as never;
 }
 
+function installSessionStorage(t: TestContext, aggregateQuota = Number.POSITIVE_INFINITY) {
+  const storage = new Map<string, string>();
+  const previousStorage = globalThis.localStorage;
+  Object.defineProperty(globalThis, 'localStorage', {
+    configurable: true,
+    value: {
+      getItem: (key: string) => storage.get(key) ?? null,
+      setItem: (key: string, value: string) => {
+        const storedBytes = [...storage].reduce((total, [storedKey, storedValue]) => (
+          total + (storedKey === key ? 0 : Buffer.byteLength(storedKey + storedValue))
+        ), 0);
+        if (storedBytes + Buffer.byteLength(key + value) > aggregateQuota) {
+          throw new DOMException('aggregate quota exceeded', 'QuotaExceededError');
+        }
+        storage.set(key, value);
+      },
+      removeItem: (key: string) => { storage.delete(key); },
+    },
+  });
+  __resetBackupMirrorForTests();
+  t.after(() => {
+    __resetBackupMirrorForTests();
+    Object.defineProperty(globalThis, 'localStorage', { configurable: true, value: previousStorage });
+  });
+  storage.set(STORAGE_KEY_CLOUD_SYNC_AI_SESSIONS, JSON.stringify({ enabled: false }));
+  return storage;
+}
+
+function makeLargeSessions(count = 4) {
+  return Array.from({ length: count }, (_, index) => makeSession(
+    `large-${index}`, count - index,
+    Array.from({ length: 200 }, (_, messageIndex) => ({
+      id: `message-${messageIndex}`,
+      role: messageIndex % 2 ? 'assistant' : 'user',
+      content: 'x'.repeat(5 * 1024 + 128),
+      timestamp: messageIndex,
+    })),
+  ));
+}
+
+test('local-only writes retain four full large chats across overflow chunks and prewarming', (t) => {
+  const storage = installSessionStorage(t);
+  const sessions = freezeHistory(makeLargeSessions());
+  assert.ok(JSON.stringify(sessions).length > 2 * 1024 * 1024);
+  assert.equal(writeSessionsForStorage(sessions), true);
+  const primary = JSON.parse(storage.get(STORAGE_KEY_AI_SESSIONS)!) as AISession[];
+  assert.ok(primary.length < sessions.length);
+  assert.ok(storage.has(`${STORAGE_KEY_AI_SESSIONS_OVERFLOW}_2`));
+  for (const [key, value] of storage) {
+    if (key.startsWith(STORAGE_KEY_AI_SESSIONS_OVERFLOW) || key === STORAGE_KEY_AI_SESSIONS) {
+      assert.ok(value.length <= 2 * 1024 * 1024);
+    }
+  }
+  assert.deepEqual(readSessionsFromStorage(), sessions);
+  // A later write of the reloaded history must retain the overflow again.
+  assert.equal(writeSessionsForStorage(readSessionsFromStorage()), true);
+  assert.deepEqual(readSessionsFromStorage(), sessions);
+  const previousSessions = latestAISessionsSnapshot;
+  try {
+    setLatestAISessionsSnapshot(null as unknown as AISession[]);
+    prewarmAIStateStorageSnapshots();
+    assert.deepEqual(latestAISessionsSnapshot, sessions);
+  } finally {
+    setLatestAISessionsSnapshot(previousSessions as AISession[]);
+  }
+});
+
+test('backup includes overflow chats before the primary blob is replaced', (t) => {
+  installSessionStorage(t);
+  const backupWrites: string[] = [];
+  const previousWindow = globalThis.window;
+  Object.defineProperty(globalThis, 'window', {
+    configurable: true,
+    value: { netcatty: { aiSessionsBackupWrite: async ({ json }: { json: string }) => {
+      backupWrites.push(json);
+      return { ok: true };
+    } } },
+  });
+  t.after(() => Object.defineProperty(globalThis, 'window', { configurable: true, value: previousWindow }));
+  const sessions = makeLargeSessions();
+  const setItem = globalThis.localStorage.setItem;
+  t.mock.method(globalThis.localStorage, 'setItem', (key: string, value: string) => {
+    if (key === STORAGE_KEY_AI_SESSIONS) {
+      flushBackupMirror();
+      assert.deepEqual(JSON.parse(backupWrites[0]), sessions);
+    }
+    setItem(key, value);
+  });
+  assert.equal(writeSessionsForStorage(sessions), true);
+  flushBackupMirror();
+  assert.equal(backupWrites.length, 1);
+  const primary = JSON.parse(localStorageAdapter.readString(STORAGE_KEY_AI_SESSIONS)!) as AISession[];
+  const primaryIds = new Set(primary.map(session => session.id));
+  assert.ok(sessions.some(session => !primaryIds.has(session.id)));
+});
+
+test('shrinking local history removes stale overflow chunks and deleted chats', (t) => {
+  const storage = installSessionStorage(t);
+  const sessions = makeLargeSessions();
+  assert.equal(writeSessionsForStorage(sessions), true);
+  assert.equal(writeSessionsForStorage(sessions.slice(0, 2)), true);
+  assert.ok(storage.has(STORAGE_KEY_AI_SESSIONS_OVERFLOW));
+  assert.equal(storage.has(`${STORAGE_KEY_AI_SESSIONS_OVERFLOW}_2`), false);
+  assert.deepEqual(readSessionsFromStorage(), sessions.slice(0, 2));
+  assert.equal(writeSessionsForStorage([sessions[0]]), true);
+  assert.equal(storage.has(STORAGE_KEY_AI_SESSIONS_OVERFLOW), false);
+  assert.deepEqual(readSessionsFromStorage(), [sessions[0]]);
+  assert.equal(writeSessionsForStorage([]), true);
+  assert.deepEqual(readSessionsFromStorage(), []);
+});
+
+test('merged storage deduplicates primary and overflow by the newer updatedAt', (t) => {
+  const storage = installSessionStorage(t);
+  const primary = [makeSession('primary-newer', 3, []), makeSession('overflow-newer', 1, [])];
+  const overflow = [makeSession('primary-newer', 2, []), makeSession('overflow-newer', 4, [])];
+  storage.set(STORAGE_KEY_AI_SESSIONS, JSON.stringify(primary));
+  storage.set(STORAGE_KEY_AI_SESSIONS_OVERFLOW, JSON.stringify(overflow));
+  assert.deepEqual(readSessionsFromStorage(), [overflow[1], primary[0]]);
+});
+
+test('the 50-session count cap still applies to primary plus overflow', (t) => {
+  installSessionStorage(t);
+  const sessions = Array.from({ length: 51 }, (_, index) => makeSession(`session-${index}`, index, [{
+    id: 'm', role: 'user', content: 'x'.repeat(50 * 1024), timestamp: 0,
+  }]));
+  assert.equal(writeSessionsForStorage(sessions), true);
+  const loaded = readSessionsFromStorage();
+  assert.equal(loaded.length, 50);
+  assert.deepEqual(loaded.map(session => session.id), sessions.slice(1).reverse().map(session => session.id));
+});
+
+test('cloud sync restores overflow if its full authoritative write fails', (t) => {
+  const storage = installSessionStorage(t);
+  assert.equal(writeSessionsForStorage(makeLargeSessions()), true);
+  const originalOverflow = storage.get(STORAGE_KEY_AI_SESSIONS_OVERFLOW);
+  storage.set(STORAGE_KEY_CLOUD_SYNC_AI_SESSIONS, JSON.stringify({ enabled: true }));
+  const before = new Map(storage);
+  const sessions = [makeSession('synced', 5, [])];
+  const writeString = localStorageAdapter.writeString;
+  const write = t.mock.method(localStorageAdapter, 'writeString', (key: string, value: string) => (
+    key === STORAGE_KEY_AI_SESSIONS ? false : writeString(key, value)
+  ));
+  assert.equal(writeSessionsForStorage(sessions), false);
+  assert.equal(storage.get(STORAGE_KEY_AI_SESSIONS_OVERFLOW), originalOverflow);
+  assert.deepEqual(storage, before);
+  const error = new Error('unexpected primary write failure');
+  write.mock.mockImplementation((key: string, value: string) => {
+    if (key === STORAGE_KEY_AI_SESSIONS) throw error;
+    return writeString(key, value);
+  });
+  assert.throws(() => writeSessionsForStorage(sessions), candidate => candidate === error);
+  assert.deepEqual(storage, before);
+  write.mock.restore();
+  assert.equal(writeSessionsForStorage(sessions), true);
+  assert.equal([...storage.keys()].some(key => key.startsWith(STORAGE_KEY_AI_SESSIONS_OVERFLOW)), false);
+  assert.deepEqual(readSessionsFromStorage(), sessions);
+});
+
+test('enabling cloud sync frees overflow quota for the authoritative primary', (t) => {
+  const storage = installSessionStorage(t, 5 * 1024 * 1024);
+  const sessions = freezeHistory(makeLargeSessions());
+  assert.equal(writeSessionsForStorage(sessions), true);
+  assert.ok(storage.has(STORAGE_KEY_AI_SESSIONS_OVERFLOW));
+  storage.set(STORAGE_KEY_CLOUD_SYNC_AI_SESSIONS, JSON.stringify({ enabled: true }));
+  assert.equal(writeSessionsForStorage(sessions), true);
+  assert.equal([...storage.keys()].some(key => key.startsWith(STORAGE_KEY_AI_SESSIONS_OVERFLOW)), false);
+  assert.deepEqual(JSON.parse(storage.get(STORAGE_KEY_AI_SESSIONS)!), sessions);
+  assert.deepEqual(readSessionsFromStorage(), sessions);
+});
+
+test('aggregate quota retries shed replay bulk from overflow and retain every chat', (t) => {
+  const storage = installSessionStorage(t, 5 * 1024 * 1024);
+  const sessions = freezeHistory(Array.from({ length: 6 }, (_, index) => makeSession(
+    `bulk-${index}`, 6 - index, [{
+      id: `message-${index}`,
+      role: 'assistant',
+      content: 'x'.repeat(700 * 1024),
+      timestamp: index,
+      toolResults: [{ toolCallId: `call-${index}`, content: 'z'.repeat(300 * 1024) }],
+      providerContinuation: {
+        reasoningParts: [{ text: '', providerOptions: { openai: {
+          reasoningEncryptedContent: 'c'.repeat(100 * 1024),
+        } } }],
+      },
+    }],
+  )));
+  assert.ok(JSON.stringify(sessions).length > 5 * 1024 * 1024);
+  const writes = t.mock.method(localStorageAdapter, 'writeString');
+  assert.equal(writeSessionsForStorage(sessions), true);
+  assert.ok(writes.mock.calls.some(call => call.result === false));
+  const primary = JSON.parse(storage.get(STORAGE_KEY_AI_SESSIONS)!) as AISession[];
+  assert.equal(primary[0].id, sessions[0].id);
+  const overflow = JSON.parse([...storage]
+    .filter(([key]) => key.startsWith(STORAGE_KEY_AI_SESSIONS_OVERFLOW))
+    .map(([, value]) => value).join('')) as AISession[];
+  assert.ok(overflow.length > 0);
+  assert.ok(overflow.every(session => {
+    const message = session.messages[0];
+    return (message.toolResults?.[0].content.length ?? 0) <= 8 * 1024
+      && !JSON.stringify(message.providerContinuation).includes('reasoningEncryptedContent');
+  }));
+  const loaded = readSessionsFromStorage();
+  assert.deepEqual(loaded.map(session => session.id), sessions.map(session => session.id));
+  assert.deepEqual(loaded.map(session => session.messages[0].content), sessions.map(session => session.messages[0].content));
+});
+
+test('a smaller primary reclaims quota before overflow when the final history fits', (t) => {
+  const storage = installSessionStorage(t, 5 * 1024 * 1024);
+  const chat = (id: string, updatedAt: number, mib: number) => makeSession(id, updatedAt, [{
+    id: 'm', role: 'user', content: 'x'.repeat(Math.floor(mib * 1024 * 1024)), timestamp: 0,
+  }]);
+  const previous = [chat('old-primary', 2, 1.9), chat('old-overflow', 1, 1.5)];
+  assert.equal(writeSessionsForStorage(previous), true);
+  const next = [chat('new-primary', 3, 1.1), ...previous];
+  assert.equal(writeSessionsForStorage(next), true);
+  assert.deepEqual(JSON.parse(storage.get(STORAGE_KEY_AI_SESSIONS)!), [next[0]]);
+  assert.deepEqual(readSessionsFromStorage(), next);
+  assert.equal(storage.has(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW), false);
+});
+
+test('overflow failure rolls back a replaced primary and the previous overflow', (t) => {
+  const storage = installSessionStorage(t, 5 * 1024 * 1024);
+  const previous = makeLargeSessions();
+  assert.equal(writeSessionsForStorage(previous), true);
+  const before = new Map(storage);
+  const writeString = localStorageAdapter.writeString;
+  const error = new Error('overflow write failed');
+  let failOnce = true;
+  t.mock.method(localStorageAdapter, 'writeString', (key: string, value: string) => {
+    if (failOnce && key === STORAGE_KEY_AI_SESSIONS_OVERFLOW) {
+      failOnce = false;
+      assert.notEqual(storage.get(STORAGE_KEY_AI_SESSIONS), before.get(STORAGE_KEY_AI_SESSIONS));
+      throw error;
+    }
+    return writeString(key, value);
+  });
+  assert.throws(() => writeSessionsForStorage([
+    { ...previous[0], title: 'New primary' }, ...previous.slice(1),
+  ]), candidate => candidate === error);
+  assert.deepEqual(storage, before);
+});
+
+test('aggregate quota falls back to a current primary with full backup and persists later turns', (t) => {
+  const storage = installSessionStorage(t, 5 * 1024 * 1024);
+  assert.equal(writeSessionsForStorage([makeSession('previous-primary', 0, [])]), true);
+  __resetBackupMirrorForTests();
+  const backupWrites: string[] = [];
+  const previousWindow = globalThis.window;
+  Object.defineProperty(globalThis, 'window', {
+    configurable: true,
+    value: { netcatty: { aiSessionsBackupWrite: async ({ json }: { json: string }) => {
+      backupWrites.push(json);
+      return { ok: true };
+    } } },
+  });
+  t.after(() => Object.defineProperty(globalThis, 'window', { configurable: true, value: previousWindow }));
+  const sessions = freezeHistory(makeLargeSessions(6));
+  assert.ok(JSON.stringify(sessions).length > 5 * 1024 * 1024);
+  const setItem = globalThis.localStorage.setItem;
+  t.mock.method(globalThis.localStorage, 'setItem', (key: string, value: string) => {
+    if (key === STORAGE_KEY_AI_SESSIONS) {
+      // The full intended history must be scheduled before replacing the old
+      // valid primary, including on the subsequent mutation of the same chat.
+      flushBackupMirror();
+      assert.equal((JSON.parse(backupWrites.at(-1)!) as AISession[]).length, 6);
+    }
+    setItem(key, value);
+  });
+  assert.equal(writeSessionsForStorage(sessions), true);
+  flushBackupMirror();
+  assert.deepEqual(JSON.parse(backupWrites.at(-1)!), sessions);
+  assert.deepEqual(readSessionsFromStorage(), [sessions[0]]);
+  assert.deepEqual(JSON.parse(storage.get(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW)!), sessions.slice(1).map(session => session.id));
+  assert.equal([...storage.keys()].some(key => key.startsWith(STORAGE_KEY_AI_SESSIONS_OVERFLOW)), false);
+
+  const updated = sessions.map((session, index) => index === 0 ? {
+    ...session,
+    updatedAt: session.updatedAt + 1,
+    messages: [...session.messages.slice(1), {
+      id: 'new-turn', role: 'user' as const, content: 'Latest turn survives reload', timestamp: 1000,
+    }],
+  } : session);
+  assert.equal(writeSessionsForStorage(updated), true);
+  flushBackupMirror();
+  assert.deepEqual(JSON.parse(backupWrites.at(-1)!), updated);
+  assert.deepEqual(JSON.parse(storage.get(STORAGE_KEY_AI_SESSIONS)!), [updated[0]]);
+  assert.deepEqual(readSessionsFromStorage(), [updated[0]]);
+});
+
+test('live writes resolve only the disk-only IDs included in primary or overflow', (t) => {
+  const storage = installSessionStorage(t);
+  const sessions = makeLargeSessions();
+  storage.set(STORAGE_KEY_AI_SESSIONS, JSON.stringify([sessions[0]]));
+  storage.set(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW, JSON.stringify([
+    sessions[0].id, sessions[1].id, 'unrecovered', 'deleted',
+  ]));
+  assert.equal(writeSessionsForStorage(sessions, { deletedSessionIds: ['deleted'] }), true);
+  assert.deepEqual(readSessionsFromStorage(), sessions);
+  assert.deepEqual(JSON.parse(storage.get(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW)!), ['unrecovered']);
+
+  // Reusing the same immutable array must still process explicit deletion,
+  // including when the primary itself has not changed.
+  assert.equal(writeSessionsForStorage(sessions, { deletedSessionIds: ['unrecovered'] }), true);
+  assert.equal(storage.has(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW), false);
+});
+
+test('same-array primary writes preserve pending recovery until explicit deletion or sync', (t) => {
+  const storage = installSessionStorage(t);
+  const sessions = [makeSession('primary', 1, [])];
+  assert.equal(writeSessionsForStorage(sessions), true);
+  storage.set(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW, JSON.stringify(['unrecovered']));
+  assert.equal(writeSessionsForStorage(sessions), true);
+  assert.deepEqual(JSON.parse(storage.get(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW)!), ['unrecovered']);
+  assert.equal(writeSessionsForStorage(sessions, { deletedSessionIds: ['unrecovered'] }), true);
+  assert.equal(storage.has(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW), false);
+
+  storage.set(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW, JSON.stringify(['unrecovered']));
+  storage.set(STORAGE_KEY_CLOUD_SYNC_AI_SESSIONS, JSON.stringify({ enabled: true }));
+  assert.equal(writeSessionsForStorage(sessions), true);
+  assert.equal(storage.has(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW), false);
+});
+
+test('tiny newest chat bounds overflow writes under aggregate quota and preserves unresolved IDs', (t) => {
+  const storage = installSessionStorage(t, 512 * 1024);
+  const sessions = [makeSession('empty-newest', 10, []), ...Array.from({ length: 3 }, (_, index) => (
+    makeSession(`huge-older-${index}`, 3 - index, [{
+      id: 'm', role: 'user', content: 'x'.repeat(768 * 1024), timestamp: 0,
+    }])
+  ))];
+  storage.set(STORAGE_KEY_AI_SESSIONS, JSON.stringify([sessions[0]]));
+  storage.set(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW, JSON.stringify(['unrecovered']));
+  const writes = t.mock.method(globalThis.localStorage, 'setItem');
+  assert.equal(writeSessionsForStorage(sessions), true);
+  assert.ok(writes.mock.callCount() < 150, `bounded writes: ${writes.mock.callCount()}`);
+  assert.deepEqual(readSessionsFromStorage(), [sessions[0]]);
+  assert.deepEqual(JSON.parse(storage.get(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW)!), [
+    'unrecovered', ...sessions.slice(1).map(session => session.id),
+  ]);
+});
+
+test('primary-only fallback frees primary quota before writing recovery metadata', (t) => {
+  const storage = installSessionStorage(t);
+  const previous = [makeSession('old-primary', 1, [{
+    id: 'm', role: 'user', content: 'x'.repeat(64 * 1024), timestamp: 0,
+  }])];
+  const previousJson = JSON.stringify(previous);
+  const sessions = [makeSession('empty-newest', 10, []), ...makeLargeSessions(2)];
+  storage.set(STORAGE_KEY_AI_SESSIONS, previousJson);
+  // The old primary fills the quota. Metadata fits only after it is replaced.
+  const aggregateQuota = [...storage].reduce((total, [key, value]) => total + key.length + value.length, 0);
+  const setItem = globalThis.localStorage.setItem;
+  t.mock.method(globalThis.localStorage, 'setItem', (key: string, value: string) => {
+    const total = [...storage].reduce((sum, [storedKey, storedValue]) => (
+      sum + (storedKey === key ? 0 : storedKey.length + storedValue.length)
+    ), key.length + value.length);
+    if (total > aggregateQuota) throw new DOMException('aggregate quota exceeded', 'QuotaExceededError');
+    setItem(key, value);
+  });
+  assert.equal(writeSessionsForStorage(sessions), true);
+  assert.deepEqual(readSessionsFromStorage(), [sessions[0]]);
+  assert.deepEqual(JSON.parse(storage.get(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW)!), sessions.slice(1).map(session => session.id));
+});
+
+test('primary-only fallback rolls back when recovery metadata cannot be written', (t) => {
+  const storage = installSessionStorage(t);
+  const previous = [makeSession('previous', 0, [])];
+  assert.equal(writeSessionsForStorage(previous), true);
+  storage.set(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW, JSON.stringify(['unrecovered']));
+  const before = new Map(storage);
+  const setItem = globalThis.localStorage.setItem;
+  t.mock.method(globalThis.localStorage, 'setItem', (key: string, value: string) => {
+    if (key.startsWith(STORAGE_KEY_AI_SESSIONS_OVERFLOW) || key === STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW) {
+      throw new DOMException('quota exceeded', 'QuotaExceededError');
+    }
+    setItem(key, value);
+  });
+  assert.equal(writeSessionsForStorage([makeSession('new', 1, []), ...makeLargeSessions(2)]), false);
+  assert.deepEqual(storage, before);
+});
+
+test('unchanged primary does not hide modified overflow from the write cache', (t) => {
+  const storage = installSessionStorage(t);
+  const sessions = freezeHistory(makeLargeSessions());
+  assert.equal(writeSessionsForStorage(sessions), true);
+  storage.set(STORAGE_KEY_AI_SESSIONS_OVERFLOW, 'corrupt overflow');
+  assert.equal(writeSessionsForStorage(sessions), true);
+  assert.deepEqual(readSessionsFromStorage(), sessions);
+});
+
+test('quota failures retain the previous overflow and back up the intended full set', (t) => {
+  const storage = installSessionStorage(t);
+  const original = makeLargeSessions();
+  assert.equal(writeSessionsForStorage(original), true);
+  __resetBackupMirrorForTests();
+  const before = new Map(storage);
+  const next = original.map(session => ({ ...session, title: 'Changed', updatedAt: session.updatedAt + 10 }));
+  t.mock.method(localStorageAdapter, 'writeString', (key: string, value: string) => {
+    if (key === STORAGE_KEY_AI_SESSIONS) return false;
+    storage.set(key, value);
+    return true;
+  });
+  const backupWrites: string[] = [];
+  const previousWindow = globalThis.window;
+  Object.defineProperty(globalThis, 'window', {
+    configurable: true,
+    value: { netcatty: { aiSessionsBackupWrite: async ({ json }: { json: string }) => {
+      backupWrites.push(json);
+      return { ok: true };
+    } } },
+  });
+  t.after(() => Object.defineProperty(globalThis, 'window', { configurable: true, value: previousWindow }));
+  assert.equal(writeSessionsForStorage(next), false);
+  assert.deepEqual(storage, before);
+  assert.deepEqual(readSessionsFromStorage(), original);
+  flushBackupMirror();
+  assert.deepEqual(JSON.parse(backupWrites[0]), next);
+});
+
 test('orphan cleanup preserves resumable privacy maps until explicit chat deletion', (t) => {
   const service = createAiPrivacyService({ maxSessions: 3 });
   service.configure({ enabled: true });
@@ -90,7 +520,10 @@ test('orphan cleanup preserves resumable privacy maps until explicit chat deleti
   const previousWindow = globalThis.window;
   const previousSessions = latestAISessionsSnapshot;
   const previousActiveSessionMap = latestAIActiveSessionMapSnapshot;
+  t.mock.method(localStorageAdapter, 'read', () => null);
+  t.mock.method(localStorageAdapter, 'readString', () => null);
   t.mock.method(localStorageAdapter, 'write', () => true);
+  t.mock.method(localStorageAdapter, 'writeString', () => true);
   Object.defineProperty(globalThis, 'window', {
     configurable: true,
     value: {
@@ -122,8 +555,24 @@ test('orphan cleanup preserves resumable privacy maps until explicit chat deleti
   try {
     cleanupOrphanedAISessions(new Set(['open', 'resumed-into']));
 
-    assert.equal(latestAISessionsSnapshot, sessions);
+    // Issue #4015 R2: the dropped chat is marked dangling but its record and
+    // its active pointer stay intact so /chats can offer a rebind.
+    const persistedSessions = latestAISessionsSnapshot;
+    assert.ok(persistedSessions);
+    assert.equal(
+      persistedSessions.find((session) => session.id === 'privacy-orphan')?.scopeDangling,
+      true,
+    );
+    assert.equal(
+      persistedSessions.find((session) => session.id === 'privacy-live')?.scopeDangling,
+      undefined,
+    );
+    assert.equal(
+      persistedSessions.find((session) => session.id === 'privacy-resumed')?.scopeDangling,
+      undefined,
+    );
     assert.deepEqual(latestAIActiveSessionMapSnapshot, {
+      'terminal:closed': 'privacy-orphan',
       'terminal:open': 'privacy-live',
       'terminal:resumed-into': 'privacy-resumed',
     });
@@ -158,6 +607,97 @@ test('orphan cleanup preserves resumable privacy maps until explicit chat deleti
   }
 });
 
+test('orphan cleanup marks dangling chats instead of stripping them, and clears the flag when the target returns', (t) => {
+  const previousSessions = latestAISessionsSnapshot;
+  const previousActiveSessionMap = latestAIActiveSessionMapSnapshot;
+  const read = t.mock.method(localStorageAdapter, 'read', () => null);
+  t.mock.method(localStorageAdapter, 'readString', () => null);
+  t.mock.method(localStorageAdapter, 'write', () => true);
+  const writeString = t.mock.method(localStorageAdapter, 'writeString', () => true);
+  const previousWindow = globalThis.window;
+  Object.defineProperty(globalThis, 'window', {
+    configurable: true,
+    value: { dispatchEvent: () => true, netcatty: {} },
+  });
+  const dangling = {
+    ...makeSession('dangling-chat', 1, []),
+    scope: { type: 'terminal' as const, targetId: 'closed-ws' },
+  };
+  const live = {
+    ...makeSession('live-chat', 2, []),
+    scope: { type: 'terminal' as const, targetId: 'open' },
+  };
+  setLatestAISessionsSnapshot([dangling, live]);
+  setLatestAIActiveSessionMapSnapshot({
+    'terminal:closed-ws': 'dangling-chat',
+    'terminal:open': 'live-chat',
+  });
+
+  try {
+    cleanupOrphanedAISessions(new Set(['open']));
+
+    let persisted = latestAISessionsSnapshot;
+    assert.ok(persisted);
+    assert.equal(persisted.find((s) => s.id === 'dangling-chat')?.scopeDangling, true);
+    assert.equal(persisted.find((s) => s.id === 'live-chat')?.scopeDangling, undefined);
+    // The active pointer survives the dangling marking.
+    assert.deepEqual(latestAIActiveSessionMapSnapshot, {
+      'terminal:closed-ws': 'dangling-chat',
+      'terminal:open': 'live-chat',
+    });
+    assert.ok(writeString.mock.callCount() > 0);
+
+    // The scope target becomes live again → the dangling flag clears.
+    read.mock.mockImplementation(() => null);
+    cleanupOrphanedAISessions(new Set(['open', 'closed-ws']));
+    persisted = latestAISessionsSnapshot;
+    assert.ok(persisted);
+    assert.equal(persisted.find((s) => s.id === 'dangling-chat')?.scopeDangling, undefined);
+  } finally {
+    setLatestAISessionsSnapshot(previousSessions ?? []);
+    setLatestAIActiveSessionMapSnapshot(previousActiveSessionMap ?? {});
+    Object.defineProperty(globalThis, 'window', {
+      configurable: true,
+      value: previousWindow,
+    });
+  }
+});
+
+test('orphan cleanup with an empty live-target set marks all scoped chats dangling', (t) => {
+  const previousSessions = latestAISessionsSnapshot;
+  const previousActiveSessionMap = latestAIActiveSessionMapSnapshot;
+  t.mock.method(localStorageAdapter, 'read', () => null);
+  t.mock.method(localStorageAdapter, 'readString', () => null);
+  t.mock.method(localStorageAdapter, 'write', () => true);
+  t.mock.method(localStorageAdapter, 'writeString', () => true);
+  const previousWindow = globalThis.window;
+  Object.defineProperty(globalThis, 'window', {
+    configurable: true,
+    value: { dispatchEvent: () => true, netcatty: {} },
+  });
+  const orphan = {
+    ...makeSession('orphan-chat', 1, []),
+    scope: { type: 'terminal' as const, targetId: 'gone' },
+  };
+  setLatestAISessionsSnapshot([orphan]);
+  setLatestAIActiveSessionMapSnapshot({ 'terminal:gone': 'orphan-chat' });
+
+  try {
+    // Empty is a valid observed live set (nothing mounted), not "unknown".
+    cleanupOrphanedAISessions(new Set());
+    const persisted = latestAISessionsSnapshot;
+    assert.ok(persisted);
+    assert.equal(persisted.find((s) => s.id === 'orphan-chat')?.scopeDangling, true);
+  } finally {
+    setLatestAISessionsSnapshot(previousSessions ?? []);
+    setLatestAIActiveSessionMapSnapshot(previousActiveSessionMap ?? {});
+    Object.defineProperty(globalThis, 'window', {
+      configurable: true,
+      value: previousWindow,
+    });
+  }
+});
+
 test('serializeSessionsForStorage strips oldest ciphertext before dropping visible sessions', async () => {
   const { serializeSessionsForStorage } = await import('./aiStateSnapshots');
   const ciphertext = 'gAAAA'.repeat(50000); // ~250 KB of ciphertext per message
@@ -518,49 +1058,26 @@ test('writeSessionsForStorage retries below nominal budgets after a quota failur
   }
 });
 
-test('writeSessionsForStorage reduces several small sessions to fit a sub-512 KB quota', async () => {
-  const { writeSessionsForStorage } = await import('./aiStateSnapshots');
+test('writeSessionsForStorage splits overflow to fit a sub-512 KB per-key quota', (t) => {
+  const storage = installSessionStorage(t);
   const writes: string[] = [];
-  let stored: string | undefined;
-  const previousLocalStorage = globalThis.localStorage;
-  Object.defineProperty(globalThis, 'localStorage', {
-    configurable: true,
-    value: {
-      getItem: () => null,
-      setItem: (_key: string, value: string) => {
-        writes.push(value);
-        if (value.length > 300 * 1024) {
-          throw new DOMException('quota exceeded', 'QuotaExceededError');
-        }
-        stored = value;
-      },
-      removeItem: () => {},
-    },
+  t.mock.method(globalThis.localStorage, 'setItem', (key: string, value: string) => {
+    writes.push(value);
+    if (value.length > 300 * 1024) {
+      throw new DOMException('quota exceeded', 'QuotaExceededError');
+    }
+    storage.set(key, value);
   });
-
-  try {
-    const sessions = Array.from({ length: 10 }, (_, index) => makeSession(
-      `session-${index}`,
-      10 - index,
-      [{
-        id: `message-${index}`,
-        role: 'user' as const,
-        content: 'x'.repeat(40 * 1024),
-        timestamp: index,
-      }],
-    ));
-
-    assert.equal(writeSessionsForStorage(sessions), true);
-    assert.ok(writes[0].length > 300 * 1024);
-    assert.ok(stored);
-    assert.ok(stored.length <= 300 * 1024);
-    assert.ok((JSON.parse(stored) as AISession[]).length < sessions.length);
-  } finally {
-    Object.defineProperty(globalThis, 'localStorage', {
-      configurable: true,
-      value: previousLocalStorage,
-    });
-  }
+  const sessions = Array.from({ length: 10 }, (_, index) => makeSession(
+    `session-${index}`, 10 - index,
+    [{ id: `message-${index}`, role: 'user', content: 'x'.repeat(40 * 1024), timestamp: index }],
+  ));
+  assert.equal(writeSessionsForStorage(sessions), true);
+  assert.ok(writes[0].length > 300 * 1024);
+  const primary = storage.get(STORAGE_KEY_AI_SESSIONS)!;
+  assert.ok(primary.length <= 300 * 1024);
+  assert.ok((JSON.parse(primary) as AISession[]).length < sessions.length);
+  assert.deepEqual(readSessionsFromStorage(), sessions);
 });
 
 test('serializeSessionsForStorage truncates slightly-over-cap tool results to strictly smaller sizes', async () => {
@@ -672,50 +1189,26 @@ test('writeSessionsForStorage keeps every chat by shedding tool output under quo
   }
 });
 
-test('writeSessionsForStorage makes a final attempt with only the newest session', async () => {
-  const { writeSessionsForStorage } = await import('./aiStateSnapshots');
+test('writeSessionsForStorage makes a final attempt with the newest primary and keeps overflow', (t) => {
+  const storage = installSessionStorage(t);
   const writes: string[] = [];
-  let stored: string | undefined;
-  const previousLocalStorage = globalThis.localStorage;
-  Object.defineProperty(globalThis, 'localStorage', {
-    configurable: true,
-    value: {
-      getItem: () => null,
-      setItem: (_key: string, value: string) => {
-        writes.push(value);
-        if (value.length > 50 * 1024) {
-          throw new DOMException('quota exceeded', 'QuotaExceededError');
-        }
-        stored = value;
-      },
-      removeItem: () => {},
-    },
+  t.mock.method(globalThis.localStorage, 'setItem', (key: string, value: string) => {
+    writes.push(value);
+    if (value.length > 50 * 1024) {
+      throw new DOMException('quota exceeded', 'QuotaExceededError');
+    }
+    storage.set(key, value);
   });
-
-  try {
-    const sessions = Array.from({ length: 10 }, (_, index) => makeSession(
-      `session-${index}`,
-      10 - index,
-      [{
-        id: `message-${index}`,
-        role: 'user' as const,
-        content: 'x'.repeat(40 * 1024),
-        timestamp: index,
-      }],
-    ));
-
-    assert.equal(writeSessionsForStorage(sessions), true);
-    assert.equal(writes.length, 6);
-    assert.ok(stored);
-    const persisted = JSON.parse(stored) as AISession[];
-    assert.deepEqual(persisted.map(session => session.id), ['session-0']);
-    assert.ok(stored.length <= 50 * 1024);
-  } finally {
-    Object.defineProperty(globalThis, 'localStorage', {
-      configurable: true,
-      value: previousLocalStorage,
-    });
-  }
+  const sessions = Array.from({ length: 10 }, (_, index) => makeSession(
+    `session-${index}`, 10 - index,
+    [{ id: `message-${index}`, role: 'user', content: 'x'.repeat(40 * 1024), timestamp: index }],
+  ));
+  assert.equal(writeSessionsForStorage(sessions), true);
+  assert.ok(writes.some(value => value.length > 50 * 1024));
+  const primary = storage.get(STORAGE_KEY_AI_SESSIONS)!;
+  assert.deepEqual((JSON.parse(primary) as AISession[]).map(session => session.id), ['session-0']);
+  assert.ok(primary.length <= 50 * 1024);
+  assert.deepEqual(readSessionsFromStorage(), sessions);
 });
 
 function freezeHistory<T>(value: T): T {
@@ -791,18 +1284,18 @@ test('synced storage bypasses fit-first pruning and non-quota failures still pro
   const { writeSessionsForStorage } = await import('./aiStateSnapshots');
   const sessions = freezeHistory(makePersistenceHistory(51, 201));
   const read = t.mock.method(localStorageAdapter, 'read', () => ({ enabled: true }));
-  const write = t.mock.method(localStorageAdapter, 'write', () => false);
-  const writeString = t.mock.method(localStorageAdapter, 'writeString', () => true);
+  t.mock.method(localStorageAdapter, 'readString', () => null);
+  const writeString = t.mock.method(localStorageAdapter, 'writeString', () => false);
   assert.equal(writeSessionsForStorage(sessions), false);
-  assert.equal(write.mock.callCount(), 1);
-  assert.equal(write.mock.calls[0].arguments[1], sessions);
-  assert.equal(writeString.mock.callCount(), 0);
+  // Synced: one write of the complete, unpruned history (serialized once).
+  assert.equal(writeString.mock.callCount(), 1);
+  assert.equal(writeString.mock.calls[0].arguments[1], JSON.stringify(sessions));
 
   read.mock.mockImplementation(() => ({ enabled: false }));
   const error = new Error('non-quota storage failure');
   writeString.mock.mockImplementation(() => { throw error; });
   assert.throws(() => writeSessionsForStorage(sessions), candidate => candidate === error);
-  assert.equal(writeString.mock.callCount(), 1);
+  assert.equal(writeString.mock.callCount(), 2);
 });
 
 for (const [budget, expectedCalls] of [[128 * 1024, 160], [0, 161]]) {
@@ -817,3 +1310,89 @@ for (const [budget, expectedCalls] of [[128 * 1024, 160], [0, 161]]) {
     assert.equal(result.sessions.length, budget === 0 ? 1 : 4);
   });
 }
+test('successful store writes schedule a throttled disk backup mirror', async (t) => {
+  const { writeSessionsForStorage, flushBackupMirror, __resetBackupMirrorForTests } =
+    await import('./aiStateSnapshots');
+  __resetBackupMirrorForTests();
+  const backupWrites: string[] = [];
+  const previousWindow = globalThis.window;
+  Object.defineProperty(globalThis, 'window', {
+    configurable: true,
+    value: {
+      netcatty: {
+        aiSessionsBackupWrite: async (payload: { json: string }) => {
+          backupWrites.push(payload.json);
+          return { ok: true };
+        },
+      },
+    },
+  });
+  const sessions = freezeHistory(makePersistenceHistory(3, 10));
+  const writeString = t.mock.method(localStorageAdapter, 'writeString', () => true);
+  t.mock.method(localStorageAdapter, 'read', () => null);
+  t.mock.method(localStorageAdapter, 'readString', () => null);
+  try {
+    assert.equal(writeSessionsForStorage(sessions), true);
+    // Throttled: nothing has been written to disk yet.
+    assert.equal(backupWrites.length, 0);
+    flushBackupMirror();
+    assert.equal(backupWrites.length, 1);
+    // The mirror carries exactly the JSON that landed in localStorage.
+    assert.equal(backupWrites[0], writeString.mock.calls[0].arguments[1]);
+    // A failed shrinking write still mirrors the full count-capped history.
+    writeString.mock.mockImplementation(() => false);
+    assert.equal(writeSessionsForStorage(sessions), false);
+    flushBackupMirror();
+    assert.equal(backupWrites.length, 2);
+    assert.deepEqual(JSON.parse(backupWrites[1]), sessions);
+  } finally {
+    __resetBackupMirrorForTests();
+    Object.defineProperty(globalThis, 'window', {
+      configurable: true,
+      value: previousWindow,
+    });
+  }
+});
+
+test('rebindActiveSessionMap drops stale pointers and sets the new scope', () => {
+  const cleaned = rebindActiveSessionMap(
+    {
+      'terminal:old-ws': 'chat-1',
+      'terminal:other': 'chat-2',
+      'workspace:keep': 'chat-1',
+    },
+    'chat-1',
+    'terminal:new-ws',
+  );
+  assert.deepEqual(cleaned, {
+    'terminal:other': 'chat-2',
+    'terminal:new-ws': 'chat-1',
+  });
+  // Idempotent when already bound to the target scope with no other pointers.
+  assert.deepEqual(
+    rebindActiveSessionMap({ 'terminal:new-ws': 'chat-1' }, 'chat-1', 'terminal:new-ws'),
+    { 'terminal:new-ws': 'chat-1' },
+  );
+});
+
+test('rewriting the same sessions array skips re-serialization while storage still holds it', async (t) => {
+  const { writeSessionsForStorage } = await import('./aiStateSnapshots');
+  const sessions = freezeHistory(makePersistenceHistory(3, 10));
+  let stored: string | null = null;
+  t.mock.method(localStorageAdapter, 'read', () => ({ enabled: true }));
+  const writeString = t.mock.method(localStorageAdapter, 'writeString', (_key: string, value: string) => {
+    stored = value;
+    return true;
+  });
+  t.mock.method(localStorageAdapter, 'readString', (key: string) => key === STORAGE_KEY_AI_SESSIONS ? stored : null);
+  assert.equal(writeSessionsForStorage(sessions), true);
+  const stringify = t.mock.method(JSON, 'stringify');
+  // Cloud-sync collection writes the same immutable array again.
+  assert.equal(writeSessionsForStorage(sessions), true);
+  assert.equal(writeString.mock.callCount(), 1);
+  assert.equal(stringify.mock.callCount(), 0);
+  // Another window replaced the store: write again.
+  stored = '[]';
+  assert.equal(writeSessionsForStorage(sessions), true);
+  assert.equal(writeString.mock.callCount(), 2);
+});

application/state/aiStateSnapshots.ts

@@ -2,6 +2,8 @@ import { localStorageAdapter } from '../../infrastructure/persistence/localStora
 import {
   STORAGE_KEY_AI_ACTIVE_SESSION_MAP,
   STORAGE_KEY_AI_SESSIONS,
+  STORAGE_KEY_AI_SESSIONS_OVERFLOW,
+  STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW,
   STORAGE_KEY_CLOUD_SYNC_AI_SESSIONS,
 } from '../../infrastructure/config/storageKeys';
 import type {
@@ -20,14 +22,17 @@ import {
 } from './aiDraftState';
 import {
   pruneInactiveScopedSessions,
-  pruneInactiveScopedTransientState,
+  pruneInactiveScopedState,
 } from './aiScopeCleanup';
 import { emitAIStateChanged } from './aiStateEvents';
-import { getAgentRuntime } from '../../infrastructure/ai/harness/globalAgentRuntime';
+import { peekAgentRuntimeCleanup } from '../../infrastructure/ai/harness/agentRuntimeHandle';
+import { setReversibleModelPrivacy } from '../../infrastructure/ai/harness/modelSecretRedaction';
+import { DebouncedBackupMirror, mergeImportedSessions, readLiveSessionsArray } from './aiSessionsBackup';
 
 /** Typed accessor for the Electron IPC bridge exposed on `window.netcatty`. */
 export interface AIBridge {
   aiSdkAgentCleanup?: (chatSessionId: string) => Promise<{ ok: boolean }>;
+  aiPrivacyClearSession?: (chatSessionId: string) => Promise<{ ok: boolean; error?: string }>;
   deleteChatToolOutputsTemp?: (chatSessionId: string) => Promise<{ deletedCount: number }>;
   deleteTerminalToolOutputsEverywhereTemp?: (terminalSessionId: string) => Promise<{ deletedCount: number }>;
   aiMcpSetPermissionMode?: (mode: AIPermissionMode) => Promise<unknown> | unknown;
@@ -35,6 +40,11 @@ export interface AIBridge {
   aiMcpSetCommandBlocklist?: (blocklist: string[]) => Promise<unknown> | unknown;
   aiMcpSetCommandTimeout?: (timeout: number) => Promise<unknown> | unknown;
   aiMcpSetMaxIterations?: (maxIterations: number) => Promise<unknown> | unknown;
+  /** Durability mirror: write one timestamped backup generation to disk. */
+  aiSessionsBackupWrite?: (payload: { json: string }) => Promise<{ ok: boolean }>;
+  aiSessionsBackupReadLatest?: () => Promise<{ ok: boolean; json?: string }>;
+  aiSessionsBackupExport?: (payload: { json: string }) => Promise<{ success: boolean; filePath?: string }>;
+  aiSessionsBackupImport?: () => Promise<{ success: boolean; json?: string }>;
 }
 
 export function getAIBridge() {
@@ -57,8 +67,18 @@ export async function cleanupSdkAgentSessions(sessionIds: string[]): Promise<voi
 export function cleanupDeletedAIChatSessions(sessionIds: string[]) {
   const bridge = getAIBridge();
   if (sessionIds.length === 0) return;
+  // Only the startup-light handle is imported here; the runtime registers it
+  // when created. Without a runtime there is no in-memory runtime state, but
+  // the reversible-privacy flag (set outside the runtime) and the
+  // main-process privacy mapping may still exist, so always clear those.
+  const runtime = peekAgentRuntimeCleanup();
   for (const sessionId of sessionIds) {
-    getAgentRuntime().clearChatSession(sessionId);
+    if (runtime) {
+      runtime.clearChatSession(sessionId);
+    } else {
+      setReversibleModelPrivacy(sessionId, false);
+      void bridge?.aiPrivacyClearSession?.(sessionId).catch(() => {});
+    }
     void bridge?.aiSdkAgentCleanup?.(sessionId).catch(() => {});
     void bridge?.deleteChatToolOutputsTemp?.(sessionId).catch(() => {});
   }
@@ -66,8 +86,9 @@ export function cleanupDeletedAIChatSessions(sessionIds: string[]) {
 
 export function cleanupClosedTerminalSessions(terminalSessionIds: string[]) {
   const bridge = getAIBridge();
+  const runtime = peekAgentRuntimeCleanup();
   for (const terminalSessionId of new Set(terminalSessionIds)) {
-    getAgentRuntime().clearTerminalSession(terminalSessionId);
+    runtime?.clearTerminalSession(terminalSessionId);
     void bridge?.deleteTerminalToolOutputsEverywhereTemp?.(terminalSessionId).catch(() => {});
   }
 }
@@ -82,10 +103,13 @@ function isScopeKeyActive(scopeKey: string, activeTargetIds: Set<string>) {
   return activeTargetIds.has(targetId);
 }
 
+/** Last live terminal/workspace target ids observed by orphan cleanup. */
+export let latestAIActiveTargetIdsSnapshot: Set<string> = new Set();
+
 export function cleanupOrphanedAISessions(activeTargetIds: Set<string>) {
+  latestAIActiveTargetIdsSnapshot = activeTargetIds;
   const currentSessions = latestAISessionsSnapshot
-    ?? localStorageAdapter.read<AISession[]>(STORAGE_KEY_AI_SESSIONS)
-    ?? [];
+    ?? readSessionsFromStorage();
 
   // Sessions shown by a still-live scope must be protected from cleanup
   // even when their own `scope.targetId` points at a closed terminal —
@@ -111,65 +135,69 @@ export function cleanupOrphanedAISessions(activeTargetIds: Set<string>) {
     cleanupSdkAgentSessions(nextSessionCleanup.orphanedSessionIds);
   }
 
-  if (nextSessionCleanup.sessions !== currentSessions) {
-    setLatestAISessionsSnapshot(nextSessionCleanup.sessions);
-    writeSessionsForStorage(nextSessionCleanup.sessions);
+  // Issue #4015 R2: a dropped chat is recoverable now, so mark it dangling
+  // instead of stripping its record or pointer. `/chats` lists dangling chats
+  // with a rebind affordance; the flag clears when the chat is rebound or its
+  // scope target becomes live again.
+  const orphanedIds = new Set(nextSessionCleanup.orphanedSessionIds);
+  let sessionsMarked = false;
+  const markedSessions = currentSessions.map((session) => {
+    if (orphanedIds.has(session.id)) {
+      if (session.scopeDangling) return session;
+      sessionsMarked = true;
+      return { ...session, scopeDangling: true };
+    }
+    if (
+      session.scopeDangling
+      && (!session.scope.targetId || activeTargetIds.has(session.scope.targetId))
+    ) {
+      sessionsMarked = true;
+      const { scopeDangling: _cleared, ...rest } = session;
+      return rest as AISession;
+    }
+    return session;
+  });
+
+  if (sessionsMarked) {
+    setLatestAISessionsSnapshot(markedSessions);
+    // Startup cleanup can run before the disk backup read resolves. Defer
+    // persistence until those chats are merged, preserving their recovery
+    // marker and avoiding a partial backup of only the loaded sessions.
+    const diskOnlyIds = localStorageAdapter.read<string[]>(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW) ?? [];
+    const loadedIds = new Set(markedSessions.map(session => session.id));
+    if (!diskOnlyIds.some(id => !loadedIds.has(id))) {
+      writeSessionsForStorage(markedSessions);
+    }
     emitAIStateChanged(STORAGE_KEY_AI_SESSIONS);
   }
 
-  const activeSessionIdMap = preCleanupActiveSessionMap;
-  let activeSessionMapChanged = false;
-  const nextActiveSessionIdMap = { ...activeSessionIdMap };
-
-  for (const scopeKey of Object.keys(activeSessionIdMap)) {
-    if (isScopeKeyActive(scopeKey, activeTargetIds)) continue;
-    delete nextActiveSessionIdMap[scopeKey];
-    activeSessionMapChanged = true;
-  }
-
-  if (activeSessionMapChanged) {
-    setLatestAIActiveSessionMapSnapshot(nextActiveSessionIdMap);
-    localStorageAdapter.write(STORAGE_KEY_AI_ACTIVE_SESSION_MAP, nextActiveSessionIdMap);
-    emitAIStateChanged(STORAGE_KEY_AI_ACTIVE_SESSION_MAP);
-  }
-
-  const currentActiveSessionIdMap = activeSessionMapChanged
-    ? nextActiveSessionIdMap
-    : activeSessionIdMap;
+  // Issue #4015 R2: keep active-pointer entries for scopes whose target
+  // closed. Clearing them used to make dangling chats invisible (rank 0) and
+  // unrecoverable from the UI; the pointer is rewritten on rebind instead.
   const currentDraftsByScope = latestAIDraftsByScopeSnapshot ?? {};
   const currentPanelViewByScope = latestAIPanelViewByScopeSnapshot ?? {};
-  const prunedScopedTransientState = pruneInactiveScopedTransientState(
-    currentActiveSessionIdMap,
+  const prunedScopedState = pruneInactiveScopedState(
     currentDraftsByScope,
     currentPanelViewByScope,
     activeTargetIds,
   );
 
-  if (prunedScopedTransientState.activeSessionIdMap !== currentActiveSessionIdMap) {
-    setLatestAIActiveSessionMapSnapshot(prunedScopedTransientState.activeSessionIdMap);
-    localStorageAdapter.write(
-      STORAGE_KEY_AI_ACTIVE_SESSION_MAP,
-      prunedScopedTransientState.activeSessionIdMap,
-    );
-    emitAIStateChanged(STORAGE_KEY_AI_ACTIVE_SESSION_MAP);
-  }
-
-  if (prunedScopedTransientState.draftsByScope !== currentDraftsByScope) {
+  if (prunedScopedState.draftsByScope !== currentDraftsByScope) {
     for (const scopeKey of Object.keys(currentDraftsByScope)) {
-      if (scopeKey in prunedScopedTransientState.draftsByScope) continue;
+      if (scopeKey in prunedScopedState.draftsByScope) continue;
       bumpDraftMutationVersion(scopeKey);
       bumpDraftUploadGeneration(scopeKey);
     }
-    setLatestAIDraftsByScopeSnapshot(prunedScopedTransientState.draftsByScope);
+    setLatestAIDraftsByScopeSnapshot(prunedScopedState.draftsByScope);
     emitAIStateChanged(AI_STATE_CHANGED_DRAFTS_BY_SCOPE);
   }
 
-  if (prunedScopedTransientState.panelViewByScope !== currentPanelViewByScope) {
+  if (prunedScopedState.panelViewByScope !== currentPanelViewByScope) {
     for (const scopeKey of Object.keys(currentPanelViewByScope)) {
-      if (scopeKey in prunedScopedTransientState.panelViewByScope) continue;
+      if (scopeKey in prunedScopedState.panelViewByScope) continue;
       bumpDraftMutationVersion(scopeKey);
     }
-    setLatestAIPanelViewByScopeSnapshot(prunedScopedTransientState.panelViewByScope);
+    setLatestAIPanelViewByScopeSnapshot(prunedScopedState.panelViewByScope);
     emitAIStateChanged(AI_STATE_CHANGED_PANEL_VIEW_BY_SCOPE);
   }
 }
@@ -180,10 +208,9 @@ const MAX_STORED_SESSIONS = 50;
 /** Maximum number of messages per session when persisting to localStorage. */
 const MAX_SESSION_MESSAGES = 200;
 /**
- * Byte budget for the serialized sessions JSON. The localStorage quota is
- * ~5-10 MB across all keys, and Responses reasoning ciphertext can add tens
- * of KB per turn, so keep the sessions blob well under the quota with
- * headroom for the rest of the app's storage keys.
+ * String-length budget for the primary sessions JSON and each overflow chunk.
+ * Replay bulk is shed from the primary blob first; whole sessions that still
+ * do not fit are retained in overflow rather than silently evicted.
  */
 const MAX_SESSIONS_JSON_BYTES = 2 * 1024 * 1024;
 /** Retry budgets used when the primary budget still fails to persist. */
@@ -349,6 +376,10 @@ export function pruneSessionsForStorage(sessions: AISession[]): AISession[] {
   });
 }
 
+export function prepareRestoredSessions(sessions: AISession[], syncEnabled: boolean): AISession[] {
+  return syncEnabled ? sessions : pruneSessionsForStorage(sessions);
+}
+
 /**
  * Serialize sessions for localStorage under a byte budget, escalating pruning
  * as needed. Returns the JSON to persist plus the (possibly) further-pruned
@@ -482,16 +513,226 @@ export function serializeSessionsForStorage(
 }
 
 /**
- * Persist sessions to localStorage with byte-budgeted pruning and retries.
- * Returns true when the write succeeded; a false result means the payload
- * could not be persisted even after escalation (it stays memory-only).
+ * Persist sessions to localStorage with byte-budgeted primary/overflow slices.
+ * Returns true when local history was saved, possibly as a newest-primary
+ * fallback with the full history scheduled for disk backup under quota pressure.
  */
-export function writeSessionsForStorage(sessions: AISession[]): boolean {
+
+// Durability mirror (issue #4015 follow-up): every successful store write
+// also schedules a debounced disk backup so a wiped/recreated profile does
+// not take the chat history with it. Persisted history is mirrored, including
+// overflow sessions, throttled to at most one write per mutation batch.
+// Before a byte-budget drop, mirror the full
+// count-capped set even if the subsequent localStorage writes fail.
+const backupMirror = new DebouncedBackupMirror((json) => {
+  try {
+    void getAIBridge()?.aiSessionsBackupWrite?.({ json })?.catch(() => {});
+  } catch {
+    // Backup failures must never break chat persistence.
+  }
+});
+
+export function flushBackupMirror() {
+  try {
+    backupMirror.flushNow();
+  } catch {
+    // Unload and persistence must remain fail-safe.
+  }
+}
+
+export function __resetBackupMirrorForTests() {
+  backupMirror.reset();
+}
+
+export function scheduleBackupMirror(json: string) {
+  try {
+    backupMirror.schedule(json);
+  } catch {
+    // ignore
+  }
+}
+
+/**
+ * Last successful write: the same immutable sessions array is written again by
+ * the debounced save path and by cloud-sync collection, and each write used to
+ * re-serialize the whole (often multi-MB) history.
+ */
+let lastSessionsWrite: { sessions: AISession[]; synced: boolean; json: string } | null = null;
+
+function rememberSessionsWrite(sessions: AISession[], synced: boolean, json: string): void {
+  lastSessionsWrite = { sessions, synced, json };
+}
+
+function storedSessionsJsonEquals(json: string): boolean {
+  try {
+    return localStorageAdapter.readString(STORAGE_KEY_AI_SESSIONS) === json;
+  } catch {
+    return false;
+  }
+}
+
+function overflowChunkKey(index: number): string {
+  return index === 0 ? STORAGE_KEY_AI_SESSIONS_OVERFLOW : `${STORAGE_KEY_AI_SESSIONS_OVERFLOW}_${index + 1}`;
+}
+
+function readOverflowChunks(): string[] {
+  const chunks: string[] = [];
+  for (let index = 0; ; index += 1) {
+    const chunk = localStorageAdapter.readString(overflowChunkKey(index));
+    if (chunk == null) return chunks;
+    chunks.push(chunk);
+  }
+}
+
+function clearOverflowChunks(startIndex = 0) {
+  for (let index = startIndex; localStorageAdapter.readString(overflowChunkKey(index)) != null; index += 1) {
+    localStorageAdapter.remove(overflowChunkKey(index));
+  }
+}
+
+function writeDiskOverflowIds(ids: string[]): boolean {
+  if (ids.length > 0) {
+    return localStorageAdapter.write(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW, ids);
+  }
+  if (localStorageAdapter.readString(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW) != null) {
+    localStorageAdapter.remove(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW);
+  }
+  return true;
+}
+
+/** Replace the entire overflow blob; never leave a partially written JSON array. */
+function replaceOverflowChunks(chunks: string[]): boolean {
+  clearOverflowChunks();
+  let complete = false;
+  try {
+    complete = chunks.every((chunk, index) => (
+      localStorageAdapter.writeString(overflowChunkKey(index), chunk)
+    ));
+    return complete;
+  } finally {
+    if (!complete) clearOverflowChunks();
+  }
+}
+
+/** Read both local retention slices; newer copies win if a session is duplicated. */
+export function readSessionsFromStorage(): AISession[] {
+  return mergeImportedSessions(
+    readLiveSessionsArray(readOverflowChunks().join('')),
+    readLiveSessionsArray(localStorageAdapter.readString(STORAGE_KEY_AI_SESSIONS)),
+  );
+}
+
+export function writeSessionsForStorage(
+  sessions: AISession[],
+  options: { deletedSessionIds?: readonly string[] } = {},
+): boolean {
+  const synced = Boolean(
+    localStorageAdapter.read<{ enabled?: boolean }>(STORAGE_KEY_CLOUD_SYNC_AI_SESSIONS)?.enabled,
+  );
+  // Nothing to do when this exact array was already written in this mode and
+  // storage still holds that write (another window may have replaced it).
+  if (
+    lastSessionsWrite?.sessions === sessions
+    && lastSessionsWrite.synced === synced
+    && storedSessionsJsonEquals(lastSessionsWrite.json)
+    // A matching primary alone cannot establish that overflow is intact.
+    && localStorageAdapter.readString(STORAGE_KEY_AI_SESSIONS_OVERFLOW) == null
+    && localStorageAdapter.readString(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW) == null
+  ) {
+    return true;
+  }
   // Synced records are authoritative after restart: silently evicting a
   // session or turn here would turn local retention into cloud deletion.
-  if (localStorageAdapter.read<{ enabled?: boolean }>(STORAGE_KEY_CLOUD_SYNC_AI_SESSIONS)?.enabled) {
-    return localStorageAdapter.write(STORAGE_KEY_AI_SESSIONS, sessions);
+  if (synced) {
+    const json = JSON.stringify(sessions);
+    const previousChunks = readOverflowChunks();
+    // The authoritative primary replaces overflow, so free its quota first.
+    clearOverflowChunks();
+    let syncedOk = false;
+    try {
+      syncedOk = localStorageAdapter.writeString(STORAGE_KEY_AI_SESSIONS, json);
+      if (syncedOk) {
+        clearOverflowChunks();
+        if (localStorageAdapter.readString(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW) != null) {
+          localStorageAdapter.remove(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW);
+        }
+        scheduleBackupMirror(json);
+        rememberSessionsWrite(sessions, true, json);
+      }
+      return syncedOk;
+    } finally {
+      if (!syncedOk) replaceOverflowChunks(previousChunks);
+    }
   }
+  const inputIds = new Set(sessions.map(session => session.id));
+  const pruned = pruneSessionsForStorage(sessions);
+  const retainedIds = new Set(pruned.map(session => session.id));
+  const deletedIds = new Set(options.deletedSessionIds);
+  // A live write can race startup's backup read. Preserve marker IDs absent
+  // from the live input unless explicitly deleted. IDs present in the input
+  // are resolved even if the count cap evicts them; pending IDs block mirroring.
+  const diskOverflowIds = localStorageAdapter.read<unknown>(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW);
+  const unresolvedDiskIds: string[] = Array.isArray(diskOverflowIds)
+    ? diskOverflowIds.filter((id): id is string => (
+      typeof id === 'string' && !retainedIds.has(id) && !deletedIds.has(id) && !inputIds.has(id)
+    ))
+    : [];
+  let fullBackupScheduled = false;
+  const ensureFullBackup = () => {
+    if (!fullBackupScheduled && unresolvedDiskIds.length === 0) {
+      scheduleBackupMirror(JSON.stringify(pruned));
+      fullBackupScheduled = true;
+    }
+  };
+  const persistCandidate = (
+    candidate: { json: string; sessions: AISession[] },
+    budget: number,
+    chunkBudget = budget,
+  ): boolean => {
+    const primaryIds = new Set(candidate.sessions.map(session => session.id));
+    const omitted = pruned.filter(session => !primaryIds.has(session.id));
+    if (omitted.length > 0) ensureFullBackup();
+    // Apply the same replay-bulk ladder to every overflow chat as budgets
+    // tighten. Chunking alone cannot reduce an origin's aggregate quota use.
+    const overflow = omitted.map(session => serializeSessionsForStorage([session], budget).sessions[0]);
+    const overflowJson = overflow.length > 0 ? JSON.stringify(overflow) : '';
+    // Split the array's JSON string, so even one oversized session can span
+    // chunks without losing messages. Concatenate all chunks before parsing.
+    const chunks: string[] = [];
+    // Primary budgets can shrink to a tiny empty chat. Keep overflow writes
+    // bounded independently while still supporting small per-key quotas.
+    const chunkSize = Math.max(32 * 1024, chunkBudget);
+    for (let offset = 0; offset < overflowJson.length; offset += chunkSize) {
+      chunks.push(overflowJson.slice(offset, offset + chunkSize));
+    }
+    const previousChunks = readOverflowChunks();
+    const previousPrimary = localStorageAdapter.readString(STORAGE_KEY_AI_SESSIONS);
+    let primaryWritten = false;
+    let persisted = false;
+    try {
+      // Reclaim both old slices before writing overflow: the final history may
+      // fit even when overflow plus the old, larger primary would exceed quota.
+      clearOverflowChunks();
+      if (!localStorageAdapter.writeString(STORAGE_KEY_AI_SESSIONS, candidate.json)) return false;
+      primaryWritten = true;
+      if (!replaceOverflowChunks(chunks)) return false;
+      if (!writeDiskOverflowIds(unresolvedDiskIds)) return false;
+      persisted = true;
+      if (!fullBackupScheduled && unresolvedDiskIds.length === 0) scheduleBackupMirror(candidate.json);
+      rememberSessionsWrite(sessions, false, candidate.json);
+      return true;
+    } finally {
+      if (!persisted) {
+        clearOverflowChunks();
+        if (primaryWritten) {
+          if (previousPrimary == null) localStorageAdapter.remove(STORAGE_KEY_AI_SESSIONS);
+          else localStorageAdapter.writeString(STORAGE_KEY_AI_SESSIONS, previousPrimary);
+        }
+        replaceOverflowChunks(previousChunks);
+      }
+    }
+  };
+  const primaryCandidates: { json: string; sessions: AISession[] }[] = [];
   let previousLength = Number.POSITIVE_INFINITY;
   for (const configuredBudget of [MAX_SESSIONS_JSON_BYTES, ...RETRY_SESSIONS_JSON_BYTES]) {
     // A real quota failure means the next attempt must be smaller even when
@@ -503,20 +744,60 @@ export function writeSessionsForStorage(sessions: AISession[]): boolean {
       : configuredBudget;
     const budget = Math.min(configuredBudget, reducedBudget);
     if (budget < 2) break;
-    const candidate = serializeSessionsForStorage(sessions, budget);
-    if (candidate.json.length >= previousLength) continue;
-    if (localStorageAdapter.writeString(STORAGE_KEY_AI_SESSIONS, candidate.json)) return true;
+    const candidate = serializeSessionsForStorage(pruned, budget);
+    primaryCandidates.push(candidate);
+    // Even an unchanged primary can succeed with smaller overflow chunks or
+    // more degraded overflow replay data at this retry budget.
+    if (persistCandidate(candidate, budget)) return true;
     previousLength = candidate.json.length;
   }
-  // Last resort: attempt the smallest representation this serializer can
-  // produce (the newest session with replay-only ciphertext removed). A very
-  // small amount of shared quota may still be enough to preserve that chat.
-  const minimalCandidate = serializeSessionsForStorage(sessions, 0);
-  if (
-    minimalCandidate.json.length < previousLength
-    && localStorageAdapter.writeString(STORAGE_KEY_AI_SESSIONS, minimalCandidate.json)
-  ) {
-    return true;
+  // Last resort: use the smallest primary representation (the newest chat
+  // with replay-only bulk removed), retaining other chats in overflow.
+  const minimalCandidate = serializeSessionsForStorage(pruned, 0);
+  const minimalChunkBudget = Math.min(minimalCandidate.json.length, RETRY_SESSIONS_JSON_BYTES[RETRY_SESSIONS_JSON_BYTES.length - 1]);
+  primaryCandidates.push(minimalCandidate);
+  if (persistCandidate(minimalCandidate, 0, minimalChunkBudget)) return true;
+
+  // If the complete retained set cannot fit, save the newest primary anyway.
+  // Schedule the full disk mirror before discarding overflow; do not let an
+  // old valid primary block persistence of every subsequent conversation turn.
+  ensureFullBackup();
+  const previousChunks = readOverflowChunks();
+  const previousPrimary = localStorageAdapter.readString(STORAGE_KEY_AI_SESSIONS);
+  const previousDiskOverflow = localStorageAdapter.readString(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW);
+  clearOverflowChunks();
+  let primaryWritten = false;
+  let primaryPersisted = false;
+  try {
+    for (const candidate of primaryCandidates) {
+      const primaryIds = new Set(candidate.sessions.map(session => session.id));
+      const diskOnlyIds = [...new Set([
+        ...unresolvedDiskIds,
+        ...pruned.filter(session => !primaryIds.has(session.id)).map(session => session.id),
+      ])];
+      // Replacing a large old primary can free the space needed by metadata.
+      // Roll it back below if the recovery marker still cannot be persisted.
+      if (!localStorageAdapter.writeString(STORAGE_KEY_AI_SESSIONS, candidate.json)) continue;
+      primaryWritten = true;
+      if (writeDiskOverflowIds(diskOnlyIds)) {
+        primaryPersisted = true;
+        rememberSessionsWrite(sessions, false, candidate.json);
+        return true;
+      }
+    }
+  } finally {
+    if (!primaryPersisted) {
+      if (primaryWritten) {
+        if (previousPrimary == null) localStorageAdapter.remove(STORAGE_KEY_AI_SESSIONS);
+        else localStorageAdapter.writeString(STORAGE_KEY_AI_SESSIONS, previousPrimary);
+      }
+      if (previousDiskOverflow != null) {
+        localStorageAdapter.writeString(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW, previousDiskOverflow);
+      } else if (localStorageAdapter.readString(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW) != null) {
+        localStorageAdapter.remove(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW);
+      }
+      replaceOverflowChunks(previousChunks);
+    }
   }
   console.warn(
     '[AIState] Failed to persist AI sessions within the storage quota; recent chat history may not survive a restart.',
@@ -531,6 +812,28 @@ export let latestAIPanelViewByScopeSnapshot: PanelViewByScope | null = null;
 let latestAIDraftMutationVersionByScopeSnapshot: Record<string, number> = {};
 let latestAIDraftUploadGenerationByScopeSnapshot: Record<string, number> = {};
 
+
+/**
+ * Issue #4015 R2: rewrite the active-session map when rebinding a dangling
+ * chat. Drops every pointer that still names `sessionId` under a different
+ * scope key, then sets the new scope as active. Callers must persist and
+ * publish the returned map (do not rebuild from a stale snapshot).
+ */
+export function rebindActiveSessionMap(
+  activeSessionIdMap: Record<string, string | null>,
+  sessionId: string,
+  scopeKey: string,
+): Record<string, string | null> {
+  let next = activeSessionIdMap;
+  for (const [key, id] of Object.entries(activeSessionIdMap)) {
+    if (id !== sessionId || key === scopeKey) continue;
+    if (next === activeSessionIdMap) next = { ...activeSessionIdMap };
+    delete next[key];
+  }
+  if (next[scopeKey] === sessionId) return next;
+  return { ...next, [scopeKey]: sessionId };
+}
+
 export function setLatestAISessionsSnapshot(sessions: AISession[]) {
   latestAISessionsSnapshot = sessions;
 }
@@ -543,7 +846,7 @@ export function prewarmAIStateStorageSnapshots() {
   try {
     if (latestAISessionsSnapshot === null) {
       latestAISessionsSnapshot =
-        localStorageAdapter.read<AISession[]>(STORAGE_KEY_AI_SESSIONS) ?? [];
+        readSessionsFromStorage();
     }
     if (latestAIActiveSessionMapSnapshot === null) {
       latestAIActiveSessionMapSnapshot =

application/state/commandHistoryStore.test.ts

@@ -326,3 +326,20 @@ test("an external clear also drops in-memory compose-bar recall", async () => {
 
   unsubscribe();
 });
+
+test("saving after a command and peer writes read the clear generation without parsing the history", async (t) => {
+  clearHistory();
+  recordCommand("echo fast-path", "host-fast", "linux");
+  assert.equal(flushCommandHistoryStore(), true);
+  const raw = storage.get(COMMAND_HISTORY_STORAGE_KEY)!;
+  assert.match(raw, /^\{"clearGeneration":\d+,/, "generation is serialized first");
+
+  const parse = t.mock.method(JSON, "parse");
+  recordCommand("echo fast-path-2", "host-fast", "linux");
+  assert.equal(flushCommandHistoryStore(), true);
+  // A peer window's save only needs the generation as well.
+  dispatchStorageEvent(COMMAND_HISTORY_STORAGE_KEY, storage.get(COMMAND_HISTORY_STORAGE_KEY)!, raw);
+  assert.equal(parse.mock.callCount(), 0);
+  parse.mock.restore();
+  assert.ok(queryHistory("echo fast", { hostId: "host-fast" }).some((entry) => entry.command === "echo fast-path-2"));
+});

application/state/commandHistoryStore.ts

@@ -68,33 +68,75 @@ function loadStore(): HistoryStore {
 }
 
 let saveTimer: ReturnType<typeof setTimeout> | null = null;
+let saveIdleHandle: number | null = null;
+
+const CLEAR_GENERATION_PREFIX = /^\{"clearGeneration":(\d+)[,}]/;
+
+/**
+ * The store's clear generation, read from its raw JSON without parsing the
+ * whole history (up to 10k entries, ~1.5 MB). Stores are serialized with
+ * clearGeneration first (serializeStore); other layouts fall back to a parse.
+ */
+function readRawClearGeneration(raw: string | null): number | null {
+  if (!raw) return null;
+  const match = CLEAR_GENERATION_PREFIX.exec(raw.slice(0, 48));
+  if (match) return Number(match[1]);
+  try {
+    return readClearGeneration(JSON.parse(raw) as HistoryStore);
+  } catch {
+    return null;
+  }
+}
+
+function serializeStore(store: HistoryStore): HistoryStore {
+  // Keep clearGeneration first so readRawClearGeneration can find it.
+  return { clearGeneration: readClearGeneration(store), version: store.version, entries: store.entries };
+}
 
 function persistStoreNow(store: HistoryStore): boolean {
   // A peer clear is visible in storage before its queued event is handled.
   // Never flush a cached pre-clear snapshot over that newer empty store.
-  const persisted = localStorageAdapter.read<HistoryStore>(STORAGE_KEY);
-  if (persisted && readClearGeneration(persisted) > readClearGeneration(store)) {
-    cachedStore = persisted;
-    knownClearGeneration = readClearGeneration(persisted);
-    notifyCommandHistoryCleared();
-    return true;
+  // Only the generation is needed on this per-command path; parse the stored
+  // history just in the rare case where it must be adopted.
+  const persistedGeneration = readRawClearGeneration(localStorageAdapter.readString(STORAGE_KEY));
+  if (persistedGeneration !== null && persistedGeneration > readClearGeneration(store)) {
+    const persisted = localStorageAdapter.read<HistoryStore>(STORAGE_KEY);
+    if (persisted && readClearGeneration(persisted) > readClearGeneration(store)) {
+      cachedStore = persisted;
+      knownClearGeneration = readClearGeneration(persisted);
+      notifyCommandHistoryCleared();
+      return true;
+    }
   }
-  const ok = localStorageAdapter.write(STORAGE_KEY, store);
+  const ok = localStorageAdapter.write(STORAGE_KEY, serializeStore(store));
   if (ok) return true;
   // Storage full — evict lowest scored entries (not just oldest by insertion)
   const now = Date.now();
   store.entries.sort((a, b) => scoreEntryAt(b, now) - scoreEntryAt(a, now));
   store.entries = store.entries.slice(0, Math.floor(MAX_ENTRIES / 2));
-  return localStorageAdapter.write(STORAGE_KEY, store);
+  return localStorageAdapter.write(STORAGE_KEY, serializeStore(store));
+}
+
+function hasPendingSave(): boolean {
+  return saveTimer !== null || saveIdleHandle !== null;
 }
 
 function saveStore(store: HistoryStore): void {
   cachedStore = store;
-  // Debounce saves to avoid excessive writes
-  if (saveTimer) clearTimeout(saveTimer);
+  // Debounce saves, then write when the renderer is idle: serializing the
+  // history right after Enter used to land in the middle of command output.
+  cancelPendingSave();
   saveTimer = setTimeout(() => {
-    persistStoreNow(store);
     saveTimer = null;
+    const persist = () => {
+      saveIdleHandle = null;
+      persistStoreNow(store);
+    };
+    if (typeof requestIdleCallback === "function") {
+      saveIdleHandle = requestIdleCallback(persist, { timeout: 2000 });
+    } else {
+      persist();
+    }
   }, 500);
 }
 
@@ -103,6 +145,10 @@ function cancelPendingSave(): void {
     clearTimeout(saveTimer);
     saveTimer = null;
   }
+  if (saveIdleHandle !== null) {
+    if (typeof cancelIdleCallback === "function") cancelIdleCallback(saveIdleHandle);
+    saveIdleHandle = null;
+  }
 }
 
 /**
@@ -129,26 +175,14 @@ function applyExternalCommandHistoryWrite(
   rawNewValue: string | null,
   rawOldValue: string | null,
 ): void {
-  let incomingGeneration: number | null = null;
-  if (rawNewValue) {
-    try {
-      incomingGeneration = readClearGeneration(JSON.parse(rawNewValue) as HistoryStore);
-    } catch {
-      incomingGeneration = null;
-    }
-  }
+  // Fires in every other window for each save; read just the generation.
+  const incomingGeneration = readRawClearGeneration(rawNewValue);
 
   let previousGeneration = knownClearGeneration;
   if (previousGeneration === null) {
     // A fresh popup can have compose recall before its first autocomplete query.
     // The event's old value is its baseline, even after an earlier global clear.
-    try {
-      previousGeneration = rawOldValue
-        ? readClearGeneration(JSON.parse(rawOldValue) as HistoryStore)
-        : 0;
-    } catch {
-      previousGeneration = 0;
-    }
+    previousGeneration = readRawClearGeneration(rawOldValue) ?? 0;
   }
   if (incomingGeneration !== null && incomingGeneration > previousGeneration) {
     cancelPendingSave();
@@ -156,7 +190,7 @@ function applyExternalCommandHistoryWrite(
     knownClearGeneration = incomingGeneration;
     notifyCommandHistoryCleared();
   } else {
-    if (!saveTimer) cachedStore = null;
+    if (!hasPendingSave()) cachedStore = null;
     if (incomingGeneration !== null && knownClearGeneration === null) {
       knownClearGeneration = incomingGeneration;
     }

application/state/monitorRuntimeStore.test.ts

@@ -47,3 +47,45 @@ test("renderer cursor acknowledges GPU publication separately from CPU sample an
     historyId: "history",
   });
 });
+
+test("idle runtime polls do not notify subscribers until something changes", async () => {
+  const React = await import("react");
+  const { act, create } = await import("react-test-renderer");
+  const { useMonitorSnapshot } = await import("./monitorRuntimeStore");
+  Object.assign(globalThis, { IS_REACT_ACT_ENVIRONMENT: true });
+  const idle = (takenAt: number): MonitorSnapshot => ({
+    historyMode: "replace",
+    runtimeId: "idle-poll-test",
+    epoch: 7,
+    takenAt,
+    running: [],
+    count: 0,
+    hostCount: 0,
+    activeSessions: [],
+    startedAt: {},
+    hosts: {},
+  });
+  let renders = 0;
+  function Probe() {
+    useMonitorSnapshot();
+    renders += 1;
+    return null;
+  }
+  // Later than anything earlier tests published, so this baseline wins.
+  const base = 1_000_000_000;
+  publishMonitorSnapshot(idle(base));
+  let renderer!: ReturnType<typeof create>;
+  act(() => {
+    renderer = create(React.createElement(Probe));
+  });
+  const baseline = renders;
+  act(() => {
+    for (let at = base + 1000; at <= base + 5000; at += 1000) publishMonitorSnapshot(idle(at));
+  });
+  assert.equal(renders, baseline, "unchanged idle replies must not re-render subscribers");
+  act(() => {
+    publishMonitorSnapshot({ ...idle(base + 6000), running: ["panel"], count: 1 });
+  });
+  assert.equal(renders, baseline + 1, "a real change still notifies");
+  act(() => renderer.unmount());
+});

application/state/monitorRuntimeStore.ts

@@ -14,8 +14,30 @@ const empty: MonitorSnapshot = {
 };
 let snapshot = empty;
 const listeners = new Set<() => void>();
+export function isIdleMonitorSnapshot(value: MonitorSnapshot): boolean {
+  return value.running.length === 0
+    && value.count === 0
+    && value.hostCount === 0
+    && value.activeSessions.length === 0
+    && Object.keys(value.hosts).length === 0
+    && Object.keys(value.startedAt).length === 0;
+}
+
+/** An idle runtime polled again: only `takenAt` moved, nothing to render. */
+function isUnchangedIdleSnapshot(previous: MonitorSnapshot, next: MonitorSnapshot): boolean {
+  return isIdleMonitorSnapshot(previous)
+    && isIdleMonitorSnapshot(next)
+    && previous.epoch === next.epoch
+    && previous.runtimeId === next.runtimeId
+    && Boolean(previous.unavailable) === Boolean(next.unavailable);
+}
+
 export function publishMonitorSnapshot(next: MonitorSnapshot) {
-  snapshot = mergeMonitorSnapshotHistory(snapshot, next);
+  const merged = mergeMonitorSnapshotHistory(snapshot, next);
+  // The runtime is polled even when nothing is monitored; do not wake every
+  // subscriber (host-key dialog, monitor panels) for an unchanged idle reply.
+  if (merged === snapshot || isUnchangedIdleSnapshot(snapshot, merged)) return;
+  snapshot = merged;
   for (const l of listeners) l();
 }
 export function getMonitorHistoryCursor(): MonitorHistoryCursor {

application/state/pluginHostSecurityVisibility.test.ts

@@ -1,36 +0,0 @@
-import assert from 'node:assert/strict';
-import test from 'node:test';
-import { JSDOM } from 'jsdom';
-import { observePluginHostSecurityVisibility } from './pluginHostSecurityVisibility';
-
-test('native modal yields to the host chooser, restores on dismissal, and never restores after cleanup', async () => {
-  const dom = new JSDOM('<body><div role="dialog" aria-modal="true"><div id="mount"></div></div></body>');
-  try {
-    const { document } = dom.window;
-    const calls: boolean[] = [];
-    const stop = observePluginHostSecurityVisibility(document.getElementById('mount')!, (visible) => calls.push(visible));
-    const flush = () => new Promise<void>((resolve) => dom.window.queueMicrotask(resolve));
-    assert.deepEqual(calls, []); // Its own modal does not hide the plugin.
-    const chooser = document.createElement('div');
-    chooser.dataset.hostSecuritySurface = '';
-    document.body.append(chooser);
-    await flush(); assert.deepEqual(calls, [false]);
-    chooser.remove(); await flush(); assert.deepEqual(calls, [false, true]);
-    document.body.append(chooser); await flush();
-    assert.deepEqual(calls, [false, true, false]);
-    stop(); chooser.remove(); await flush();
-    assert.deepEqual(calls, [false, true, false]);
-  } finally { dom.window.close(); }
-});
-
-test('hidden security surfaces do not occlude a native view', async () => {
-  const dom = new JSDOM('<body><div id="mount"></div><div hidden><div data-host-security-surface></div></div></body>');
-  try {
-    const calls: boolean[] = [];
-    const stop = observePluginHostSecurityVisibility(dom.window.document.getElementById('mount')!, (visible) => calls.push(visible));
-    assert.deepEqual(calls, []);
-    dom.window.document.querySelector('[hidden]')!.removeAttribute('hidden');
-    await new Promise<void>((resolve) => dom.window.queueMicrotask(resolve));
-    assert.deepEqual(calls, [false]); stop();
-  } finally { dom.window.close(); }
-});

application/state/pluginHostSecurityVisibility.ts

@@ -1,21 +0,0 @@
-/** Native plugin views must yield while a host-owned security dialog is open. */
-export function observePluginHostSecurityVisibility(mount: HTMLElement, publish: (visible: boolean) => void): () => void {
-  const document = mount.ownerDocument;
-  let visible = true;
-  const update = () => {
-    const blocked = [...document.querySelectorAll('[data-host-security-surface]')].some((surface) => {
-      const style = document.defaultView!.getComputedStyle(surface);
-      return style.display !== 'none' && style.visibility !== 'hidden'
-        && !surface.closest('[hidden], [inert], [aria-hidden="true"]');
-    });
-    if (visible === !blocked) return;
-    visible = !blocked;
-    publish(visible);
-  };
-  const observer = new document.defaultView!.MutationObserver(update);
-  observer.observe(document.body, { childList: true, subtree: true, attributes: true,
-    attributeFilter: ['class', 'style', 'hidden', 'inert', 'aria-hidden', 'data-host-security-surface'] });
-  update();
-  // The view lifecycle owns close/retention. Cleanup must never reveal an old view.
-  return () => observer.disconnect();
-}

application/state/pluginKeybindings.ts

@@ -33,6 +33,7 @@ const NAMED_KEYS = new Map<string, string>([
   ['tab', 'tab'],
 ]);
 const PLUGIN_SHORTCUT_EDITABLE_SELECTOR = [
+  '[data-plugin-editing]',
   'input',
   'textarea',
   'select',
@@ -44,6 +45,10 @@ const PLUGIN_SHORTCUT_EDITABLE_SELECTOR = [
   '.monaco-menu-container',
 ].join(', ');
 
+export function isPluginViewEditingTarget(node: EventTarget | null): boolean {
+  return Boolean((node as Element | null)?.closest?.('[data-plugin-editing]'));
+}
+
 function hasEditableShortcutAncestor(node: unknown): boolean {
   const closest = (node as { closest?: (selector: string) => unknown } | null)?.closest;
   return typeof closest === 'function'

application/state/pluginRemoteTree.test.tsx

@@ -0,0 +1,67 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { JSDOM } from 'jsdom';
+
+test('React 19 changes are staged as safe data before any host rendering', async () => {
+  const dom = new JSDOM('<!doctype html><div id="remote"></div>', { url: 'http://localhost', pretendToBeVisual: true });
+  const saved = new Map<string, PropertyDescriptor | undefined>();
+  for (const key of ['window', 'document', 'navigator', 'HTMLElement', 'Element', 'Node', 'MutationObserver', 'Event', 'MouseEvent']) {
+    saved.set(key, Object.getOwnPropertyDescriptor(globalThis, key));
+    Object.defineProperty(globalThis, key, { configurable: true, writable: true, value: key === 'window' ? dom.window : dom.window[key as keyof typeof dom.window] });
+  }
+  Object.defineProperty(globalThis, 'IS_REACT_ACT_ENVIRONMENT', { configurable: true, writable: true, value: true });
+  const { default: React, act, useState } = await import('react');
+  const { createRoot } = await import('react-dom/client');
+  const { RemoteMutationObserver } = await import('@remote-dom/core/elements');
+  const { createPluginRemoteTree } = await import('./pluginRemoteTree');
+  const staged = createPluginRemoteTree();
+  const snapshots: ReturnType<typeof staged.snapshot>[] = [];
+  const observer = new RemoteMutationObserver({
+    mutate(records) { snapshots.push(staged.apply(JSON.parse(JSON.stringify(records)))); },
+    call() { throw new Error('Host method calls are unavailable'); },
+  });
+  const container = document.getElementById('remote')!;
+  observer.observe(container);
+  const root = createRoot(container);
+  function Example() {
+    const [count, setCount] = useState(0);
+    return <section className="card" style={{ display: 'grid', gap: '12px' }}><h1>Hello</h1><button type="button" onClick={() => setCount((value) => value + 1)}>Count {count}</button></section>;
+  }
+  try {
+    await act(async () => { root.render(<Example />); await new Promise((resolve) => setTimeout(resolve, 10)); });
+    const first = snapshots.at(-1)!;
+    const section = first.children[0]; assert.equal(section.type, 1);
+    if (section.type !== 1) throw new Error('Expected section');
+    assert.equal(section.attributes.class, 'card');
+    assert.match(section.attributes.style, /display:\s*grid/);
+    await act(async () => { container.querySelector('button')!.click(); await new Promise((resolve) => setTimeout(resolve, 10)); });
+    const updated = JSON.stringify(snapshots.at(-1));
+    assert.match(updated, /Count /); assert.match(updated, /"data":"1"/);
+    assert.equal(staged.isFailed(), false);
+    assert.throws(() => staged.apply([[3, section.id, 'onclick', 'attack()']]));
+    assert.deepEqual(staged.snapshot(), { children: [] });
+    assert.equal(staged.isFailed(), true);
+    assert.throws(() => staged.apply([]));
+  } finally {
+    observer.disconnect(); await act(async () => { root.unmount(); });
+    for (const [key, value] of saved) { if (value) Object.defineProperty(globalThis, key, value); else Reflect.deleteProperty(globalThis, key); }
+    Reflect.deleteProperty(globalThis, 'IS_REACT_ACT_ENVIRONMENT'); dom.window.close();
+  }
+});
+
+test('removed attributes do not keep checkboxes, menus or old inline styles active', async () => {
+  const { createPluginRemoteTree } = await import('./pluginRemoteTree');
+  const tree = createPluginRemoteTree();
+  tree.apply([[0, '~', { id: 'control', type: 1, element: 'input', attributes: { type: 'checkbox', checked: '', style: 'color:red' }, children: [] }, 0]]);
+  const updated = tree.apply([[3, 'control', 'checked', null], [3, 'control', 'style', null]]);
+  assert.deepEqual(updated.children[0], { id: 'control', type: 1, element: 'input', attributes: { type: 'checkbox' }, children: [] });
+});
+
+test('inserting a child into an existing void element fails the view', async () => {
+  const { createPluginRemoteTree } = await import('./pluginRemoteTree');
+  const tree = createPluginRemoteTree();
+  tree.apply([[0, '~', { id: 'input', type: 1, element: 'input', attributes: {}, children: [] }, 0]]);
+  assert.throws(() => tree.apply([[0, 'input', { id: 'child', type: 3, data: 'invalid' }, 0]]), /Void view elements/);
+  assert.equal(tree.isFailed(), true);
+  assert.deepEqual(tree.snapshot(), { children: [] });
+});

application/state/pluginRemoteTree.ts

@@ -0,0 +1,41 @@
+import { RemoteReceiver } from '@remote-dom/core/receivers';
+import { validatePluginMutationBatch, validatePluginRemoteTree } from '@/domain/pluginRemoteTreePolicy.cjs';
+
+type WireNode = { id: string; type: 3 | 8; data: string } | {
+  id: string; type: 1; element: string; attributes: Record<string, string>; children: WireNode[];
+};
+type WireTree = { children: WireNode[] };
+
+/** Data-only staging area: untrusted changes are never applied directly to the host DOM. */
+export function createPluginRemoteTree() {
+  const receiver = new RemoteReceiver();
+  let current: WireTree = { children: [] };
+  let failed = false;
+  const project = (node: unknown): WireNode => {
+    const value = node as { id: string; type: number; data?: string; element?: string; attributes?: Record<string, string>; children?: unknown[] };
+    if (value.type === 3 || value.type === 8) return { id: value.id, type: value.type, data: value.data ?? '' };
+    return { id: value.id, type: 1, element: value.element ?? '', attributes: Object.fromEntries(Object.entries(value.attributes ?? {}).filter(([, attribute]) => attribute !== null)), children: (value.children ?? []).map(project) };
+  };
+  return {
+    apply(input: unknown): WireTree {
+      if (failed) throw new Error('Plugin view has been closed after an invalid update');
+      try {
+        validatePluginMutationBatch(input);
+        // Ordinary DOM attribute mutations do not specify a channel. RemoteReceiver
+        // defaults those to properties, so explicitly mark them as attributes.
+        const batch = (input as unknown[][]).map((record) => record[0] === 3 && record.length === 4 ? [...record, 2] : record);
+        receiver.connection.mutate(batch as unknown as Parameters<typeof receiver.connection.mutate>[0]);
+        const next = { children: receiver.root.children.map(project) };
+        validatePluginRemoteTree(next);
+        current = next;
+        return next;
+      } catch (error) {
+        failed = true;
+        current = { children: [] };
+        throw error;
+      }
+    },
+    snapshot(): WireTree { return current; },
+    isFailed(): boolean { return failed; },
+  };
+}

application/state/pluginViewLifecycle.test.ts

@@ -1,111 +1,7 @@
 import assert from 'node:assert/strict';
 import test from 'node:test';
-
-import {
-  PluginViewLifecycleController,
-  consumeClosedPluginViewInstance,
-  reconcilePluginViewTabCatalog,
-  markPluginViewOpenTokensClosed,
-  reconcileClosedPluginView,
-  rememberClosedPluginViewInstance,
-  resolvePluginViewSnapshotSelection,
-  shouldReconcilePluginViewTabCatalog,
-  withdrawPluginViewTab,
-  type HostedPluginViewState,
-} from './pluginViewLifecycle.ts';
-import { PluginViewTabStore } from './pluginViewTabStore.ts';
-
-function view(id: string, tabId?: string): HostedPluginViewState {
-  return {
-    id,
-    viewId: `view.${id}`,
-    scopeId: 'window:main',
-    retainContextWhenHidden: false,
-    ...(tabId ? { tabId } : {}),
-  };
-}
-
-test('host close events clear the active renderer instance and identify its native tab', () => {
-  const current = view('active', 'plugin-view:publisher.plugin:view.active');
-  const result = reconcileClosedPluginView({
-    current,
-    retained: new Map([['retained', view('retained')]]),
-    instanceId: 'active',
-  });
-
-  assert.equal(result.current, null);
-  assert.equal(result.matchedCurrent, true);
-  assert.equal(result.closedTabId, current.tabId);
-  assert.equal(result.retained.size, 1);
-});
-
-test('host close events remove retained instances without dismissing another active view', () => {
-  const current = view('active');
-  const retainedTab = view('retained-closed', 'plugin-view:publisher.plugin:view.retained');
-  const result = reconcileClosedPluginView({
-    current,
-    retained: new Map([
-      ['closed', retainedTab],
-      ['kept', view('retained-kept')],
-    ]),
-    instanceId: 'retained-closed',
-  });
-
-  assert.equal(result.current, current);
-  assert.equal(result.matchedCurrent, false);
-  assert.equal(result.matchedRetained, true);
-  assert.deepEqual([...result.retained.keys()], ['kept']);
-  assert.equal(result.closedTabId, retainedTab.tabId);
-});
-
-test('explicit native-tab close destroys active and retained instances instead of retaining them', () => {
-  const tabId = 'plugin-view:publisher.plugin:view.shared';
-  const result = withdrawPluginViewTab({
-    current: view('active', tabId),
-    retained: new Map([
-      ['same-tab', view('retained-same', tabId)],
-      ['other-tab', view('retained-other', 'plugin-view:publisher.plugin:view.other')],
-    ]),
-    tabId,
-  });
-
-  assert.equal(result.current, null);
-  assert.equal(result.matchedCurrent, true);
-  assert.equal(result.matchedRetained, true);
-  assert.deepEqual(result.instanceIds, ['active', 'retained-same']);
-  assert.deepEqual([...result.retained.keys()], ['other-tab']);
-});
-
-test('an early host close tombstone is consumed when the open response arrives later', () => {
-  const tombstones = new Set<string>();
-  rememberClosedPluginViewInstance(tombstones, 'instance-early');
-  assert.equal(consumeClosedPluginViewInstance(tombstones, 'instance-early'), true);
-  assert.equal(consumeClosedPluginViewInstance(tombstones, 'instance-early'), false);
-
-  for (let index = 0; index < 300; index += 1) {
-    rememberClosedPluginViewInstance(tombstones, `instance-${index}`);
-  }
-  assert.equal(tombstones.size, 256);
-  assert.equal(tombstones.has('instance-0'), false);
-});
-
-test('explicit close marks only in-flight opens owned by the closed surface', () => {
-  const first = Symbol('first');
-  const second = Symbol('second');
-  const explicitlyClosed = new Set<symbol>();
-  const opening = new Map<string, Set<symbol>>([
-    ['window:main\0view.first', new Set([first])],
-    ['window:main\0view.second', new Set([second])],
-  ]);
-
-  assert.equal(markPluginViewOpenTokensClosed(
-    opening,
-    explicitlyClosed,
-    'window:main\0view.first',
-  ), 1);
-  assert.deepEqual([...explicitlyClosed], [first]);
-  assert.equal(markPluginViewOpenTokensClosed(opening, explicitlyClosed, null), 0);
-});
+import { reconcilePluginViewTabCatalog, resolvePluginViewSnapshotSelection, shouldReconcilePluginViewTabCatalog } from './pluginViewLifecycle';
+import { PluginViewTabStore } from './pluginViewTabStore';
 
 test('locale-only snapshot refresh keeps the owned view alive without weakening context fail-closed behavior', () => {
   const previous = {
@@ -184,30 +80,3 @@ test('active-tab context refresh cannot withdraw the plugin tab that triggered i
   assert.equal(store.getTabs()[0]?.title, 'Localized View');
   assert.equal(activeTabId, tab.id);
 });
-
-test('lifecycle controller owns retained views, open tokens, tombstones, and teardown', () => {
-  const controller = new PluginViewLifecycleController<HostedPluginViewState>();
-  const tabId = 'plugin-view:publisher.plugin:view.shared';
-  const active = view('active', tabId);
-  const retained = view('retained');
-  controller.setCurrent(active);
-  controller.retain('window:main\0view.retained', retained);
-
-  const token = controller.beginOpen({
-    viewKey: 'window:main\0view.active',
-    tabId,
-  });
-  const closed = controller.handleTabClose(tabId);
-  assert.deepEqual(closed.instanceIds, [active.id]);
-  assert.equal(controller.shouldCloseOpen(token), true);
-  controller.finishOpen({ token, viewKey: 'window:main\0view.active', tabId });
-  assert.equal(controller.shouldCloseOpen(token), false);
-
-  const early = controller.handleHostClose('instance-before-open-response');
-  assert.equal(early.matchedCurrent, false);
-  assert.equal(early.matchedRetained, false);
-  assert.equal(controller.consumeHostClose('instance-before-open-response'), true);
-
-  assert.deepEqual(controller.drain().map((candidate) => candidate.id), [retained.id]);
-  assert.equal(controller.getCurrent(), null);
-});

application/state/pluginViewLifecycle.ts

@@ -1,11 +1,3 @@
-export interface HostedPluginViewState {
-  id: string;
-  viewId: string;
-  scopeId: string;
-  retainContextWhenHidden: boolean;
-  tabId?: string;
-}
-
 export interface PluginViewSnapshotSelection<T> {
   requestViewId: string;
   contextKey: string;
@@ -81,241 +73,3 @@ export function reconcilePluginViewTabCatalog({
   store.refreshMetadata(entries);
   return true;
 }
-
-export function reconcileClosedPluginView<T extends HostedPluginViewState>({
-  current,
-  retained,
-  instanceId,
-}: {
-  current: T | null;
-  retained: ReadonlyMap<string, T>;
-  instanceId: string;
-}): {
-  current: T | null;
-  retained: Map<string, T>;
-  matchedCurrent: boolean;
-  matchedRetained: boolean;
-  closedTabId?: string;
-} {
-  const matchedCurrent = current?.id === instanceId;
-  let matchedRetained = false;
-  let retainedTabId: string | undefined;
-  const nextRetained = new Map<string, T>();
-  for (const [key, view] of retained) {
-    if (view.id === instanceId) {
-      matchedRetained = true;
-      retainedTabId = view.tabId;
-    }
-    else nextRetained.set(key, view);
-  }
-  return {
-    current: matchedCurrent ? null : current,
-    retained: nextRetained,
-    matchedCurrent,
-    matchedRetained,
-    ...((matchedCurrent ? current?.tabId : retainedTabId)
-      ? { closedTabId: matchedCurrent ? current?.tabId : retainedTabId }
-      : {}),
-  };
-}
-
-export function withdrawPluginViewTab<T extends HostedPluginViewState>({
-  current,
-  retained,
-  tabId,
-}: {
-  current: T | null;
-  retained: ReadonlyMap<string, T>;
-  tabId: string;
-}): {
-  current: T | null;
-  retained: Map<string, T>;
-  instanceIds: string[];
-  matchedCurrent: boolean;
-  matchedRetained: boolean;
-} {
-  const matchedCurrent = current?.tabId === tabId;
-  let matchedRetained = false;
-  const instanceIds: string[] = [];
-  if (matchedCurrent && current) instanceIds.push(current.id);
-  const nextRetained = new Map<string, T>();
-  for (const [key, view] of retained) {
-    if (view.tabId === tabId) {
-      matchedRetained = true;
-      instanceIds.push(view.id);
-    } else {
-      nextRetained.set(key, view);
-    }
-  }
-  return {
-    current: matchedCurrent ? null : current,
-    retained: nextRetained,
-    instanceIds,
-    matchedCurrent,
-    matchedRetained,
-  };
-}
-
-export function rememberClosedPluginViewInstance(
-  tombstones: Set<string>,
-  instanceId: string,
-  limit = 256,
-): void {
-  if (tombstones.size >= limit) {
-    const oldest = tombstones.values().next().value;
-    if (typeof oldest === 'string') tombstones.delete(oldest);
-  }
-  tombstones.add(instanceId);
-}
-
-export function consumeClosedPluginViewInstance(tombstones: Set<string>, instanceId: string): boolean {
-  return tombstones.delete(instanceId);
-}
-
-export function markPluginViewOpenTokensClosed(
-  openingTokens: ReadonlyMap<string, ReadonlySet<symbol>>,
-  explicitlyClosedTokens: Set<symbol>,
-  ownerKey: string | null | undefined,
-): number {
-  if (!ownerKey) return 0;
-  const tokens = openingTokens.get(ownerKey);
-  if (!tokens) return 0;
-  for (const token of tokens) explicitlyClosedTokens.add(token);
-  return tokens.size;
-}
-
-export class PluginViewLifecycleController<T extends HostedPluginViewState = HostedPluginViewState> {
-  private current: T | null = null;
-  private retained = new Map<string, T>();
-  private readonly closedInstanceIds = new Set<string>();
-  private readonly openingTokensByTab = new Map<string, Set<symbol>>();
-  private readonly openingTokensByView = new Map<string, Set<symbol>>();
-  private readonly explicitlyClosedOpenTokens = new Set<symbol>();
-
-  getCurrent(): T | null {
-    return this.current;
-  }
-
-  setCurrent(view: T | null): void {
-    this.current = view;
-  }
-
-  takeCurrent(): T | null {
-    const current = this.current;
-    this.current = null;
-    return current;
-  }
-
-  retain(key: string, view: T): void {
-    this.retained.set(key, view);
-  }
-
-  takeRetained(key: string): T | null {
-    const retained = this.retained.get(key) ?? null;
-    if (retained) this.retained.delete(key);
-    return retained;
-  }
-
-  removeRetained(key: string): void {
-    this.retained.delete(key);
-  }
-
-  removeRetainedWhere(predicate: (view: T) => boolean): T[] {
-    const removed: T[] = [];
-    for (const [key, view] of this.retained) {
-      if (!predicate(view)) continue;
-      this.retained.delete(key);
-      removed.push(view);
-    }
-    return removed;
-  }
-
-  handleHostClose(instanceId: string) {
-    const next = reconcileClosedPluginView({
-      current: this.current,
-      retained: this.retained,
-      instanceId,
-    });
-    this.current = next.current;
-    this.retained = next.retained;
-    if (!next.matchedCurrent && !next.matchedRetained) {
-      rememberClosedPluginViewInstance(this.closedInstanceIds, instanceId);
-    }
-    return next;
-  }
-
-  handleTabClose(tabId: string) {
-    const next = withdrawPluginViewTab({
-      current: this.current,
-      retained: this.retained,
-      tabId,
-    });
-    this.current = next.current;
-    this.retained = next.retained;
-    markPluginViewOpenTokensClosed(
-      this.openingTokensByTab,
-      this.explicitlyClosedOpenTokens,
-      tabId,
-    );
-    return next;
-  }
-
-  markViewClosed(viewKey: string | null | undefined): number {
-    return markPluginViewOpenTokensClosed(
-      this.openingTokensByView,
-      this.explicitlyClosedOpenTokens,
-      viewKey,
-    );
-  }
-
-  beginOpen({
-    viewKey,
-    tabId,
-    label,
-  }: {
-    viewKey: string;
-    tabId?: string;
-    label?: string;
-  }): symbol {
-    const token = Symbol(label ?? tabId ?? viewKey);
-    const viewTokens = this.openingTokensByView.get(viewKey) ?? new Set<symbol>();
-    viewTokens.add(token);
-    this.openingTokensByView.set(viewKey, viewTokens);
-    if (tabId) {
-      const tabTokens = this.openingTokensByTab.get(tabId) ?? new Set<symbol>();
-      tabTokens.add(token);
-      this.openingTokensByTab.set(tabId, tabTokens);
-    }
-    return token;
-  }
-
-  finishOpen({ token, viewKey, tabId }: { token: symbol; viewKey: string; tabId?: string }): void {
-    this.explicitlyClosedOpenTokens.delete(token);
-    const viewTokens = this.openingTokensByView.get(viewKey);
-    viewTokens?.delete(token);
-    if (viewTokens?.size === 0) this.openingTokensByView.delete(viewKey);
-    if (!tabId) return;
-    const tabTokens = this.openingTokensByTab.get(tabId);
-    tabTokens?.delete(token);
-    if (tabTokens?.size === 0) this.openingTokensByTab.delete(tabId);
-  }
-
-  shouldCloseOpen(token: symbol): boolean {
-    return this.explicitlyClosedOpenTokens.has(token);
-  }
-
-  consumeHostClose(instanceId: string): boolean {
-    return consumeClosedPluginViewInstance(this.closedInstanceIds, instanceId);
-  }
-
-  drain(): T[] {
-    const values = [this.current, ...this.retained.values()].filter((view): view is T => Boolean(view));
-    this.current = null;
-    this.retained.clear();
-    this.closedInstanceIds.clear();
-    this.openingTokensByTab.clear();
-    this.openingTokensByView.clear();
-    this.explicitlyClosedOpenTokens.clear();
-    return values;
-  }
-}

application/state/pluginViewSession.test.ts

@@ -0,0 +1,41 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import type { HostDrawnViewMessage, HostDrawnViewOpenRequest } from '@netcatty/plugin-contract';
+type Update = Extract<HostDrawnViewMessage, { kind: 'host-ui.update' }> & { viewId: string };
+import { PluginViewSessions } from './pluginViewSession';
+function fixture() {
+  let updates: (data: Update) => void = () => {}; let closed: (data: NetcattyPluginViewClosedEvent) => void = () => {};
+  const opened: HostDrawnViewOpenRequest[] = []; const closes: string[] = []; const events: unknown[] = [];
+  const bridge = { openHostDrawnPluginView: async (request: HostDrawnViewOpenRequest) => { opened.push(request); return { instanceId: request.instanceId }; },
+    closeHostDrawnPluginView: async (id: string) => { closes.push(id); },
+    onHostDrawnPluginViewUpdate: (listener: typeof updates) => { updates = listener; return () => {}; },
+    onPluginViewClosed: (listener: typeof closed) => { closed = listener; return () => {}; },
+    sendHostDrawnPluginViewEvent: async (id: string, event: unknown) => { events.push({ id, event }); } };
+  return { bridge, opened, closes, events, update: (data: Update) => updates(data), close: (data: { instanceId: string }) => closed({ ...data, viewId: request.viewId, pluginId: 'com.example', reason: 'test' }) };
+}
+const request = { viewId: 'com.example.view', scopeId: 'window:one', context: {} };
+test('a hidden view resumes its existing state and plugin instance', async () => {
+  const f = fixture(); const store = new PluginViewSessions();
+  const first = store.acquire('view', f.bridge, request); const id = f.opened[0].instanceId;
+  f.update({ kind: 'host-ui.update', viewId: request.viewId, instanceId: id, sequence: 1, css: '', mutations: [[0, '~', { id: 'text', type: 3, data: 'kept' }, 0]] });
+  first.release(); const next = store.acquire('view', f.bridge, request);
+  assert.equal(next, first); assert.equal(f.opened.length, 1); assert.deepEqual(next.getSnapshot().tree.children[0], { id: 'text', type: 3, data: 'kept' });
+  next.release(); store.dispose(); await Promise.resolve(); assert.equal(new Set(f.closes).size, 1);
+});
+test('host invalidation clears retained content and a reopen creates a new instance', () => {
+  const f = fixture(); const store = new PluginViewSessions(); const old = store.acquire('view', f.bridge, request);
+  f.close({ instanceId: f.opened[0].instanceId }); assert.equal(old.getSnapshot().error, true); assert.deepEqual(old.getSnapshot().tree.children, []);
+  const next = store.acquire('view', f.bridge, request); assert.notEqual(old, next); store.dispose();
+});
+test('unacknowledged input is not overwritten by an older plugin update', () => {
+  const f = fixture(); const store = new PluginViewSessions(); const view = store.acquire('view', f.bridge, request);
+  view.send({ type: 'input', nodeId: 'field', value: 'latest' }); assert.equal(view.getSnapshot().settled, false);
+  const base = { kind: 'host-ui.update' as const, viewId: request.viewId, instanceId: f.opened[0].instanceId, css: '', mutations: [] };
+  f.update({ ...base, sequence: 1, acknowledgedEvent: 0 }); assert.equal(view.getSnapshot().settled, false);
+  f.update({ ...base, sequence: 2, acknowledgedEvent: 1 }); assert.equal(view.getSnapshot().settled, true); store.dispose();
+});
+test('idle instances are evicted while active instances are never silently replaced', () => {
+  const f = fixture(); const store = new PluginViewSessions(1); const first = store.acquire('one', f.bridge, request);
+  assert.throws(() => store.acquire('two', f.bridge, request), /Too many/); first.release();
+  const second = store.acquire('two', f.bridge, request); assert.notEqual(second, first); assert.equal(f.closes.length, 1); store.dispose();
+});

application/state/pluginViewSession.ts

@@ -0,0 +1,78 @@
+import { createPluginRemoteTree } from './pluginRemoteTree';
+import { validatePluginStylesheet } from '@/domain/pluginViewStylePolicy.cjs';
+import type { HostDrawnViewEvent } from '@netcatty/plugin-contract';
+
+type Bridge = Pick<NonNullable<ReturnType<typeof import('../../infrastructure/services/netcattyBridge').netcattyBridge.get>>, 'openHostDrawnPluginView' | 'closeHostDrawnPluginView' | 'onHostDrawnPluginViewUpdate' | 'onPluginViewClosed' | 'sendHostDrawnPluginViewEvent' | 'getPluginViewResource'>;
+export type PluginViewSnapshot = { tree: ReturnType<ReturnType<typeof createPluginRemoteTree>['snapshot']>; css: string; loading: boolean; error: boolean; settled: boolean };
+const empty = (): PluginViewSnapshot => ({ tree: { children: [] }, css: '', loading: true, error: false, settled: true });
+
+/** Owns a window's bounded, retained UI instances independently of React mounts. */
+export class PluginViewSessions {
+  private sessions = new Map<string, ReturnType<PluginViewSessions['create']>>();
+  constructor(private readonly capacity = 16, private readonly idleMs = 300_000) {}
+  private create(key: string, bridge: Bridge, request: Omit<import('@netcatty/plugin-contract').HostDrawnViewOpenRequest, 'instanceId'>) {
+    const id = crypto.randomUUID();
+    const tree = createPluginRemoteTree();
+    let state = empty(); let sequence = 1; let eventId = 0; let disposed = false; let users = 0;
+    let timer: ReturnType<typeof setTimeout> | undefined;
+    const listeners = new Set<() => void>();
+    const publish = (next: PluginViewSnapshot) => { state = next; for (const listener of listeners) listener(); };
+    const cleanup: Array<() => void> = [];
+    const dispose = (failed = false) => {
+      if (disposed) return;
+      disposed = true; clearTimeout(timer); cleanup.forEach((stop) => stop());
+      this.sessions.delete(key);
+      publish({ ...empty(), loading: false, error: failed });
+      void bridge.closeHostDrawnPluginView?.(id).catch(() => {});
+    };
+    if (!bridge.openHostDrawnPluginView || !bridge.onHostDrawnPluginViewUpdate || !bridge.onPluginViewClosed) throw new Error('Plugin views unavailable');
+    cleanup.push(bridge.onHostDrawnPluginViewUpdate((update) => {
+      if (disposed || update.kind !== 'host-ui.update' || update.instanceId !== id || update.viewId !== request.viewId) return;
+      try {
+        if (update.sequence !== sequence++) throw new Error('Invalid plugin update order');
+        publish({ tree: tree.apply(update.mutations), css: validatePluginStylesheet(update.css), loading: false, error: false, settled: (update.acknowledgedEvent ?? 0) >= eventId });
+      } catch { dispose(true); }
+    }));
+    cleanup.push(bridge.onPluginViewClosed((event) => { if (event.instanceId === id) dispose(true); }));
+    void bridge.openHostDrawnPluginView({ ...request, instanceId: id }).then(() => {
+      if (disposed) void bridge.closeHostDrawnPluginView?.(id).catch(() => {});
+    }).catch(() => dispose(true));
+    return {
+      viewId: request.viewId,
+      scope: request.scopeId,
+      image: async (path: string) => {
+        if (disposed || !bridge.getPluginViewResource) throw new Error('Plugin image unavailable');
+        const result = await bridge.getPluginViewResource({ instanceId: id, path });
+        if (disposed) throw new Error('Plugin view closed');
+        return result.url;
+      },
+      get idle() { return users === 0; },
+      getSnapshot: () => state,
+      subscribe(listener: () => void) { listeners.add(listener); return () => { listeners.delete(listener); }; },
+      acquire: () => { clearTimeout(timer); users++; },
+      release: () => { if (--users === 0 && !disposed) timer = setTimeout(() => dispose(), this.idleMs); },
+      send: (event: HostDrawnViewEvent) => {
+        if (disposed || users === 0) return;
+        publish({ ...state, settled: false });
+        void bridge.sendHostDrawnPluginViewEvent?.(id, { ...event, eventId: ++eventId }).catch(() => dispose(true));
+      },
+      dispose,
+    };
+  }
+  acquire(key: string, bridge: Bridge, request: Omit<import('@netcatty/plugin-contract').HostDrawnViewOpenRequest, 'instanceId'>) {
+    let session = this.sessions.get(key);
+    if (!session) {
+      while (this.sessions.size >= this.capacity) {
+        const candidate = [...this.sessions.values()].find((item) => item.idle);
+        if (!candidate) throw new Error('Too many open plugin views');
+        candidate.dispose();
+      }
+      session = this.create(key, bridge, request); this.sessions.set(key, session);
+    }
+    session.acquire(); return session;
+  }
+  closeView(viewId: string) { for (const session of [...this.sessions.values()]) if (session.viewId === viewId) session.dispose(); }
+  closeScope(scope: string) { for (const session of [...this.sessions.values()]) if (session.scope === scope) session.dispose(); }
+  dispose() { for (const session of [...this.sessions.values()]) session.dispose(); }
+}
+export const pluginViewSessions = new PluginViewSessions();

application/state/sftp/useSftpFollowTerminalCwd.ts

@@ -393,12 +393,10 @@ export function useSftpFollowTerminalCwd({
       handledFollowRef.current = { connectionId: currentConnection.id, terminalCwd: targetPath };
     }
   }, [
-    activeSessionId,
     activeTerminalCwd,
     activeTerminalCwdTrusted,
     canFollowTerminalCwd,
     effectiveFollowTerminalCwd,
-    focusedSessionId,
     hasActiveWork,
     isVisible,
     onGetTerminalCwd,

application/state/terminalReconnectRegistry.test.ts

@@ -3,6 +3,37 @@ import test from 'node:test';
 
 import { createTerminalReconnectRegistry } from './terminalReconnectRegistry';
 
+test('recovery snapshots use the current handler and disappear on unmount', () => {
+  const registry = createTerminalReconnectRegistry();
+  assert.equal(registry.inspect('s'), null);
+  const unregister = registry.register('s', () => {}, () => false,
+    () => ({ status: 'disconnected', waitingForInput: true, reconnecting: false }));
+  assert.equal(registry.inspect('s')?.waitingForInput, true);
+  assert.equal(registry.inspect('s')?.reconnectAllowed, false);
+  unregister();
+  assert.equal(registry.inspect('s'), null);
+});
+
+test('agent reconnect never queues an unmounted terminal', () => {
+  const registry = createTerminalReconnectRegistry();
+  assert.equal(registry.requestIfAvailable('missing'), false);
+  let calls = 0;
+  registry.register('missing', () => { calls++; });
+  assert.equal(calls, 0);
+});
+
+test('agent reconnect respects live eligibility and active reconnects', () => {
+  const registry = createTerminalReconnectRegistry();
+  let eligible = false;
+  let calls = 0;
+  registry.register('s', () => { calls++; registry.setActive('s', true); }, () => eligible);
+  assert.equal(registry.requestIfAvailable('s'), false);
+  eligible = true;
+  assert.equal(registry.requestIfAvailable('s'), true);
+  assert.equal(registry.requestIfAvailable('s'), false);
+  assert.equal(calls, 1);
+});
+
 test('a registered terminal session can be reconnected on request', () => {
   const registry = createTerminalReconnectRegistry();
   const requestedSessionIds: string[] = [];

application/state/terminalReconnectRegistry.ts

@@ -1,7 +1,10 @@
 type TerminalReconnectHandler = () => void;
+export type TerminalRecoverySnapshot = { status: string; waitingForInput: boolean; reconnecting: boolean; stopped?: boolean };
 
 export const createTerminalReconnectRegistry = () => {
   const handlers = new Map<string, TerminalReconnectHandler>();
+  const eligibility = new Map<string, () => boolean>();
+  const recoveryReaders = new Map<string, () => TerminalRecoverySnapshot>();
   const pendingRequests = new Set<string>();
   const activeSessionIds = new Set<string>();
   const enterReconnectEnabledIds = new Set<string>();
@@ -28,19 +31,40 @@ export const createTerminalReconnectRegistry = () => {
     return () => listeners.delete(listener);
   };
 
-  const register = (sessionId: string, handler: TerminalReconnectHandler): (() => void) => {
+  const register = (sessionId: string, handler: TerminalReconnectHandler,
+    canReconnect: () => boolean = () => false, readRecovery?: () => TerminalRecoverySnapshot): (() => void) => {
     handlers.set(sessionId, handler);
+    eligibility.set(sessionId, canReconnect);
+    if (readRecovery) recoveryReaders.set(sessionId, readRecovery);
+    else recoveryReaders.delete(sessionId);
     if (pendingRequests.delete(sessionId)) {
       handler();
     }
     return () => {
       if (handlers.get(sessionId) === handler) {
         handlers.delete(sessionId);
+        eligibility.delete(sessionId);
+        recoveryReaders.delete(sessionId);
         setActive(sessionId, false);
       }
     };
   };
 
+  const inspect = (sessionId: string) => {
+    const state = recoveryReaders.get(sessionId)?.();
+    if (!state) return null;
+    return { ...state, reconnecting: state.reconnecting || isActive(sessionId),
+      reconnectAllowed: !isActive(sessionId) && Boolean(eligibility.get(sessionId)?.()) };
+  };
+
+  // Agent requests must never survive unmount or bypass authentication/auto-retry.
+  const requestIfAvailable = (sessionId: string): boolean => {
+    const handler = handlers.get(sessionId);
+    if (!handler || isActive(sessionId) || !eligibility.get(sessionId)?.()) return false;
+    handler();
+    return true;
+  };
+
   const request = (sessionId: string): boolean => {
     if (isActive(sessionId)) return false;
     const handler = handlers.get(sessionId);
@@ -66,7 +90,9 @@ export const createTerminalReconnectRegistry = () => {
 
   return {
     register,
+    inspect,
     request,
+    requestIfAvailable,
     requestEnterReconnect,
     setEnterReconnectEnabled,
     setActive,

application/state/terminalSidePanelPluginTabs.test.tsx

@@ -0,0 +1,44 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { JSDOM } from 'jsdom';
+
+test('plugin tools stay in the toolbar and retain placement across catalog changes and remount', async () => {
+  const dom = new JSDOM('<!doctype html><div id="root"></div>', { url: 'http://localhost' });
+  const previous = new Map<string, PropertyDescriptor | undefined>();
+  for (const key of ['window', 'document', 'navigator', 'localStorage', 'StorageEvent', 'CustomEvent', 'Event']) {
+    previous.set(key, Object.getOwnPropertyDescriptor(globalThis, key));
+    Object.defineProperty(globalThis, key, { configurable: true, writable: true, value: key === 'window' ? dom.window : dom.window[key as keyof typeof dom.window] });
+  }
+  Object.defineProperty(globalThis, 'IS_REACT_ACT_ENVIRONMENT', { configurable: true, writable: true, value: true });
+  const { default: React, act } = await import('react');
+  const { createRoot } = await import('react-dom/client');
+  const { useTerminalSidePanelTabOrder, TERMINAL_SIDE_PANEL_TAB_DEFAULT_ORDER } = await import('./terminalSidePanelTabs');
+  const { STORAGE_KEY_TERMINAL_SIDE_PANEL_TAB_LAYOUT } = await import('../../infrastructure/config/storageKeys');
+  const plugin = 'plugin-view:com.example.sidebar.page' as const;
+  dom.window.localStorage.setItem(STORAGE_KEY_TERMINAL_SIDE_PANEL_TAB_LAYOUT, JSON.stringify({ order: TERMINAL_SIDE_PANEL_TAB_DEFAULT_ORDER, placement: {} }));
+  let model: ReturnType<typeof useTerminalSidePanelTabOrder>;
+  let tools: typeof plugin[] = [];
+  function Fixture() { model = useTerminalSidePanelTabOrder(tools); return <div />; }
+  const root = createRoot(document.getElementById('root')!);
+  const render = async () => { await act(async () => { root.render(<Fixture />); }); };
+  try {
+    await render();
+    tools = [plugin]; await render();
+    assert.equal(model!.sidePanelTabOrder[1], plugin, 'new plugin is a visible toolbar item');
+    assert.ok(model!.partition([...TERMINAL_SIDE_PANEL_TAB_DEFAULT_ORDER, plugin]).shown.includes(plugin));
+    await act(async () => { model!.setPlacement(plugin, 'collapse', [...TERMINAL_SIDE_PANEL_TAB_DEFAULT_ORDER, plugin]); });
+    tools = []; await render();
+    assert.ok(!model!.partition(TERMINAL_SIDE_PANEL_TAB_DEFAULT_ORDER).collapsed.includes(plugin));
+    tools = [plugin]; await render();
+    assert.ok(model!.partition([...TERMINAL_SIDE_PANEL_TAB_DEFAULT_ORDER, plugin]).collapsed.includes(plugin));
+    await act(async () => { root.unmount(); });
+    const nextRoot = createRoot(document.getElementById('root')!);
+    tools = []; await act(async () => { nextRoot.render(<Fixture />); });
+    tools = [plugin]; await act(async () => { nextRoot.render(<Fixture />); });
+    assert.ok(model!.partition([...TERMINAL_SIDE_PANEL_TAB_DEFAULT_ORDER, plugin]).collapsed.includes(plugin), 'cold catalog loading preserves preference');
+    await act(async () => { nextRoot.unmount(); });
+  } finally {
+    for (const [key, descriptor] of previous) { if (descriptor) Object.defineProperty(globalThis, key, descriptor); else Reflect.deleteProperty(globalThis, key); }
+    Reflect.deleteProperty(globalThis, 'IS_REACT_ACT_ENVIRONMENT'); dom.window.close();
+  }
+});

application/state/terminalSidePanelTabs.ts

@@ -1,4 +1,4 @@
-import { useCallback, useMemo } from 'react';
+import { useCallback, useEffect, useMemo, useRef } from 'react';
 
 import {
   normalizeToolbarItemLayout,
@@ -13,7 +13,7 @@ import {
 } from '../../infrastructure/config/storageKeys';
 import { localStorageAdapter } from '../../infrastructure/persistence/localStorageAdapter';
 import { useToolbarItemLayout } from './useToolbarItemLayout';
-import type { BuiltinSidePanelTool, SidePanelTool } from '../../domain/sidePanelLayout';
+import { isPluginSidePanelTool, type BuiltinSidePanelTool, type SidePanelTool } from '../../domain/sidePanelLayout';
 
 export type TerminalSidePanelTabId = SidePanelTool;
 
@@ -101,7 +101,7 @@ function migrateSidePanelTabLayoutIfNeeded(): void {
 
 migrateSidePanelTabLayoutIfNeeded();
 
-export function useTerminalSidePanelTabOrder(): {
+export function useTerminalSidePanelTabOrder(pluginTools: readonly SidePanelTool[] = []): {
   sidePanelTabOrder: TerminalSidePanelTabId[];
   setSidePanelTabOrder: (order: TerminalSidePanelTabId[]) => void;
   layout: ToolbarItemLayout;
@@ -111,6 +111,23 @@ export function useTerminalSidePanelTabOrder(): {
   resetLayout: () => void;
   partition: ReturnType<typeof useToolbarItemLayout>['partition'];
 } {
+  // Keep preferences for temporarily unavailable/disabled plugins, including
+  // across a cold start before the contribution catalog finishes loading.
+  const knownPluginTools = useRef<Set<string> | null>(null);
+  if (!knownPluginTools.current) {
+    let stored: unknown;
+    try { stored = localStorageAdapter.read(STORAGE_KEY_TERMINAL_SIDE_PANEL_TAB_LAYOUT); } catch { stored = null; }
+    const order = stored && typeof stored === 'object' && !Array.isArray(stored)
+      ? (stored as { order?: unknown }).order : [];
+    knownPluginTools.current = new Set(Array.isArray(order)
+      ? order.filter((id): id is string => typeof id === 'string' && isPluginSidePanelTool(id)) : []);
+  }
+  for (const tool of pluginTools) if (isPluginSidePanelTool(tool)) knownPluginTools.current.add(tool);
+  const pluginKey = [...knownPluginTools.current].join('\0');
+  const defaults = useMemo<ToolbarItemLayoutDefaults>(() => {
+    const plugins = pluginKey ? pluginKey.split('\0') : [];
+    return { order: [TERMINAL_SIDE_PANEL_TAB_DEFAULT_ORDER[0], ...plugins, ...TERMINAL_SIDE_PANEL_TAB_DEFAULT_ORDER.slice(1)] };
+  }, [pluginKey]);
   const {
     layout,
     setPlacement,
@@ -121,9 +138,28 @@ export function useTerminalSidePanelTabOrder(): {
     partition,
   } = useToolbarItemLayout(
     STORAGE_KEY_TERMINAL_SIDE_PANEL_TAB_LAYOUT,
-    TERMINAL_SIDE_PANEL_TAB_LAYOUT_DEFAULTS,
+    defaults,
   );
 
+  // Newly installed plugins get a visible slot near the start even when an
+  // older saved layout already exists. Existing choices always keep their order.
+  const activePluginKey = pluginTools.filter(isPluginSidePanelTool).join('\0');
+  useEffect(() => {
+    const active = activePluginKey ? activePluginKey.split('\0') : [];
+    if (!active.length || active.some((id) => !layout.order.includes(id))) return;
+    let stored: unknown;
+    try { stored = localStorageAdapter.read(STORAGE_KEY_TERMINAL_SIDE_PANEL_TAB_LAYOUT); } catch { return; }
+    const storedOrder = stored && typeof stored === 'object' && !Array.isArray(stored)
+      ? (stored as { order?: unknown }).order : null;
+    const saved = new Set(Array.isArray(storedOrder) ? storedOrder : []);
+    const fresh = active.filter((id) => !saved.has(id));
+    if (!fresh.length) return;
+    const rest = layout.order.filter((id) => !fresh.includes(id));
+    const index = Math.max(0, rest.indexOf('sftp') + 1);
+    const next = [...rest.slice(0, index), ...fresh, ...rest.slice(index)];
+    if (next.some((id, i) => id !== layout.order[i])) setOrder(next);
+  }, [activePluginKey, layout.order, setOrder]);
+
   const sidePanelTabOrder = layout.order as TerminalSidePanelTabId[];
 
   const setSidePanelTabOrder = useCallback(

application/state/useAIState.historyRetention.test.ts

@@ -0,0 +1,456 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import React, { act } from 'react';
+import { createRoot } from 'react-dom/client';
+import { JSDOM } from 'jsdom';
+import type { AISession } from '../../infrastructure/ai/types';
+import { STORAGE_KEY_AI_ACTIVE_SESSION_MAP, STORAGE_KEY_AI_SESSIONS, STORAGE_KEY_AI_SESSIONS_OVERFLOW, STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW, STORAGE_KEY_CLOUD_SYNC_AI_SESSIONS } from '../../infrastructure/config/storageKeys';
+import { useAIState } from './useAIState';
+import { useAISessionsStore } from './aiSessionsStore';
+import { __resetBackupMirrorForTests, flushBackupMirror, readSessionsFromStorage, setLatestAIActiveSessionMapSnapshot, setLatestAISessionsSnapshot, writeSessionsForStorage } from './aiStateSnapshots';
+
+for (const enabled of [true, false]) {
+  test(`appending to long history preserves the synced prefix (chat sync ${enabled})`, async () => {
+    const dom = new JSDOM('<!doctype html><html><body></body></html>', { url: 'http://localhost' });
+    for (const name of ['window', 'document', 'localStorage', 'CustomEvent', 'Event'] as const) {
+      Object.defineProperty(globalThis, name, { configurable: true, value: name === 'window' ? dom.window : dom.window[name] });
+    }
+    Object.defineProperty(globalThis, 'IS_REACT_ACT_ENVIRONMENT', { configurable: true, value: true });
+    const source: AISession = {
+      id: 'long-chat', title: 'Long chat', agentId: 'codex', externalSessionId: 'native-thread',
+      scope: { type: 'global' }, createdAt: 1, updatedAt: 501,
+      messages: [{ id: 'system', role: 'system', content: 'Instruction', timestamp: 0 },
+        ...Array.from({ length: 500 }, (_, index) => ({ id: `message-${index}`, role: 'user' as const, content: `Prompt ${index}`, timestamp: index + 1 }))],
+    };
+    setLatestAISessionsSnapshot([source]);
+    dom.window.localStorage.setItem(STORAGE_KEY_AI_SESSIONS, JSON.stringify([source]));
+    dom.window.localStorage.setItem(STORAGE_KEY_CLOUD_SYNC_AI_SESSIONS, JSON.stringify({ enabled }));
+    let ai: ReturnType<typeof useAIState>;
+    let sessions: readonly AISession[] = [];
+    function Harness() {
+      ai = useAIState();
+      sessions = useAISessionsStore().sessions;
+      return null;
+    }
+    const container = document.createElement('div');
+    document.body.appendChild(container);
+    const root = createRoot(container);
+    try {
+      await act(async () => { root.render(React.createElement(Harness)); });
+      await act(async () => {
+        ai!.addMessageToSession(source.id, { id: 'new-reply', role: 'assistant', content: 'Continued', timestamp: 502 });
+      });
+      const updated = sessions.find(value => value.id === source.id)!;
+      assert.equal(updated.messages.length, enabled ? 502 : 500);
+      assert.equal(updated.messages[0].id, 'system');
+      assert.equal(updated.messages[1].id, enabled ? 'message-0' : 'message-2');
+      assert.equal(updated.messages.at(-1)?.id, 'new-reply');
+      assert.equal(updated.externalSessionId, 'native-thread');
+    } finally {
+      await act(async () => { root.unmount(); });
+      container.remove();
+      dom.window.close();
+    }
+  });
+}
+
+test('startup and cross-window updates load overflow chats and mirror the merged history', async () => {
+  const dom = new JSDOM('<!doctype html><html><body></body></html>', { url: 'http://localhost' });
+  for (const name of ['window', 'document', 'localStorage', 'CustomEvent', 'Event'] as const) {
+    Object.defineProperty(globalThis, name, { configurable: true, value: name === 'window' ? dom.window : dom.window[name] });
+  }
+  Object.defineProperty(globalThis, 'IS_REACT_ACT_ENVIRONMENT', { configurable: true, value: true });
+  const primary: AISession = {
+    id: 'primary', title: 'Primary', agentId: 'catty', scope: { type: 'global' },
+    createdAt: 1, updatedAt: 2, messages: [],
+  };
+  const overflow = { ...primary, id: 'overflow', title: 'Overflow', updatedAt: 1 };
+  dom.window.localStorage.setItem(STORAGE_KEY_AI_SESSIONS, JSON.stringify([primary]));
+  dom.window.localStorage.setItem(STORAGE_KEY_AI_SESSIONS_OVERFLOW, JSON.stringify([overflow]));
+  setLatestAISessionsSnapshot(null as unknown as AISession[]);
+  __resetBackupMirrorForTests();
+  const backups: string[] = [];
+  Object.assign(dom.window, { netcatty: { aiSessionsBackupWrite: async ({ json }: { json: string }) => {
+    backups.push(json);
+    return { ok: true };
+  } } });
+  let sessions: readonly AISession[] = [];
+  function Harness() {
+    useAIState();
+    sessions = useAISessionsStore().sessions;
+    return null;
+  }
+  const container = document.createElement('div');
+  document.body.appendChild(container);
+  const root = createRoot(container);
+  try {
+    await act(async () => { root.render(React.createElement(Harness)); });
+    assert.deepEqual(sessions, [primary, overflow]);
+    flushBackupMirror();
+    assert.deepEqual(JSON.parse(backups[0]), [primary, overflow]);
+    const updatedOverflow = { ...overflow, title: 'Updated elsewhere', updatedAt: 3 };
+    await act(async () => {
+      dom.window.localStorage.setItem(STORAGE_KEY_AI_SESSIONS_OVERFLOW, JSON.stringify([updatedOverflow]));
+      dom.window.dispatchEvent(new dom.window.StorageEvent('storage', { key: STORAGE_KEY_AI_SESSIONS_OVERFLOW }));
+    });
+    assert.deepEqual(sessions, [updatedOverflow, primary]);
+  } finally {
+    await act(async () => { root.unmount(); });
+    __resetBackupMirrorForTests();
+    setLatestAISessionsSnapshot([]);
+    container.remove();
+    dom.window.close();
+  }
+});
+
+for (const scopeType of ['global', 'terminal'] as const) {
+  test(`import retains disk-only chats in live history across rename and deletion (${scopeType})`, async () => {
+    const dom = new JSDOM('<!doctype html><html><body></body></html>', {
+      url: 'http://localhost', storageQuota: 5 * 1024 * 1024,
+    });
+    const previousDOMException = globalThis.DOMException;
+    for (const name of ['window', 'document', 'localStorage', 'CustomEvent', 'Event', 'DOMException'] as const) {
+      Object.defineProperty(globalThis, name, { configurable: true, value: name === 'window' ? dom.window : dom.window[name] });
+    }
+    Object.defineProperty(globalThis, 'IS_REACT_ACT_ENVIRONMENT', { configurable: true, value: true });
+    const source: AISession[] = Array.from({ length: 6 }, (_, index) => ({
+      id: `imported-${index}`, title: `Imported ${index}`, agentId: 'catty',
+      scope: scopeType === 'global' ? { type: 'global' } : { type: 'terminal', targetId: 'closed-terminal' },
+      createdAt: 1, updatedAt: 6 - index,
+      messages: [{ id: 'm', role: 'user', content: 'x'.repeat(Math.floor(1.1 * 1024 * 1024)), timestamp: 1 }],
+    }));
+    const ids = source.map(session => session.id);
+    const backups: string[] = [];
+    Object.assign(dom.window, { netcatty: {
+      aiSessionsBackupImport: async () => ({ success: true, json: JSON.stringify(source) }),
+      aiSessionsBackupWrite: async ({ json }: { json: string }) => { backups.push(json); return { ok: true }; },
+    } });
+    dom.window.localStorage.setItem(STORAGE_KEY_AI_SESSIONS, '[]');
+    setLatestAISessionsSnapshot([]);
+    setLatestAIActiveSessionMapSnapshot({});
+    __resetBackupMirrorForTests();
+    let ai!: ReturnType<typeof useAIState>;
+    let sessions: readonly AISession[] = [];
+    function Harness() {
+      ai = useAIState();
+      sessions = useAISessionsStore().sessions;
+      return null;
+    }
+    const container = document.createElement('div');
+    document.body.appendChild(container);
+    const root = createRoot(container);
+    try {
+      await act(async () => { root.render(React.createElement(Harness)); });
+      await act(async () => { ai.cleanupOrphanedSessions(new Set()); });
+      let importedCount = 0;
+      await act(async () => { importedCount = await ai.importSessionsBackup(); });
+      assert.equal(importedCount, source.length);
+      assert.deepEqual(sessions.map(session => session.id), ids);
+      assert.deepEqual(readSessionsFromStorage().map(session => session.id), [ids[0]]);
+      assert.deepEqual(JSON.parse(dom.window.localStorage.getItem(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW)!), ids.slice(1));
+      assert.equal(sessions.every(session => !!session.scopeDangling === (scopeType === 'terminal')), true);
+      flushBackupMirror();
+      assert.deepEqual(JSON.parse(backups.at(-1)!), sessions);
+
+      await act(async () => { ai.updateSessionTitle(ids[0], 'Renamed after import'); });
+      assert.deepEqual(sessions.map(session => session.id), ids);
+      assert.equal(sessions[0].title, 'Renamed after import');
+      assert.deepEqual(JSON.parse(dom.window.localStorage.getItem(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW)!), ids.slice(1));
+      flushBackupMirror();
+      assert.deepEqual(JSON.parse(backups.at(-1)!), sessions);
+
+      await act(async () => { ai.deleteSession(ids[5]); });
+      assert.deepEqual(sessions.map(session => session.id), ids.slice(0, 5));
+      assert.deepEqual(JSON.parse(dom.window.localStorage.getItem(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW)!), ids.slice(1, 5));
+      flushBackupMirror();
+      assert.deepEqual(JSON.parse(backups.at(-1)!), sessions);
+    } finally {
+      await act(async () => { root.unmount(); });
+      __resetBackupMirrorForTests();
+      setLatestAISessionsSnapshot([]);
+      setLatestAIActiveSessionMapSnapshot({});
+      container.remove();
+      dom.window.close();
+      Object.defineProperty(globalThis, 'DOMException', { configurable: true, value: previousDOMException });
+    }
+  });
+}
+
+test('startup recovers disk-only chats before mirroring a valid partial primary', async () => {
+  const dom = new JSDOM('<!doctype html><html><body></body></html>', {
+    url: 'http://localhost', storageQuota: 5 * 1024 * 1024,
+  });
+  const previousDOMException = globalThis.DOMException;
+  for (const name of ['window', 'document', 'localStorage', 'CustomEvent', 'Event', 'DOMException'] as const) {
+    Object.defineProperty(globalThis, name, { configurable: true, value: name === 'window' ? dom.window : dom.window[name] });
+  }
+  Object.defineProperty(globalThis, 'IS_REACT_ACT_ENVIRONMENT', { configurable: true, value: true });
+  const source: AISession[] = Array.from({ length: 6 }, (_, index) => ({
+    id: `chat-${index}`, title: `Chat ${index}`, agentId: 'catty', scope: { type: 'global' },
+    createdAt: 1, updatedAt: 6 - index,
+    messages: [{ id: 'm', role: 'user', content: 'x'.repeat(Math.floor(1.1 * 1024 * 1024)), timestamp: 1 }],
+  }));
+  const backups: string[] = [];
+  let reads = 0;
+  let resolveRead!: (backup: { ok: boolean; json: string }) => void;
+  Object.assign(dom.window, { netcatty: {
+    aiSessionsBackupWrite: async ({ json }: { json: string }) => { backups.push(json); return { ok: true }; },
+    aiSessionsBackupReadLatest: () => {
+      reads += 1;
+      return new Promise(resolve => { resolveRead = resolve; });
+    },
+  } });
+  __resetBackupMirrorForTests();
+  assert.equal(writeSessionsForStorage(source), true);
+  flushBackupMirror();
+  assert.deepEqual(JSON.parse(backups[0]), source);
+  assert.deepEqual(readSessionsFromStorage(), [source[0]]);
+  assert.deepEqual(JSON.parse(dom.window.localStorage.getItem(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW)!), source.slice(1).map(session => session.id));
+  // A newer local copy must win, and an old deleted chat in the backup must
+  // stay deleted: only the explicitly recorded disk-only IDs are recovered.
+  const primary = { ...source[0], title: 'Newer primary', updatedAt: 10 };
+  dom.window.localStorage.setItem(STORAGE_KEY_AI_SESSIONS, JSON.stringify([primary]));
+  const expected = [primary, ...source.slice(1)];
+  const staleBackup = JSON.stringify([...source, { ...source[5], id: 'deleted-chat' }]);
+  backups.length = 0;
+  __resetBackupMirrorForTests();
+  setLatestAISessionsSnapshot(null as unknown as AISession[]);
+  let sessions: readonly AISession[] = [];
+  function Harness() {
+    useAIState();
+    sessions = useAISessionsStore().sessions;
+    return null;
+  }
+  const container = document.createElement('div');
+  document.body.appendChild(container);
+  const root = createRoot(container);
+  try {
+    await act(async () => { root.render(React.createElement(Harness)); });
+    assert.equal(reads, 1);
+    flushBackupMirror();
+    assert.deepEqual(backups, []);
+    await act(async () => { resolveRead({ ok: true, json: staleBackup }); });
+    assert.deepEqual(sessions, expected);
+    flushBackupMirror();
+    assert.deepEqual(JSON.parse(backups.at(-1)!), expected);
+    assert.deepEqual(readSessionsFromStorage(), [primary]);
+  } finally {
+    await act(async () => { root.unmount(); });
+    __resetBackupMirrorForTests();
+    setLatestAISessionsSnapshot([]);
+    container.remove();
+    dom.window.close();
+    Object.defineProperty(globalThis, 'DOMException', { configurable: true, value: previousDOMException });
+  }
+});
+
+for (const scopeType of ['terminal', 'workspace'] as const) {
+  test(`startup orphan cleanup preserves pending disk-only recovery (${scopeType})`, async () => {
+    const dom = new JSDOM('<!doctype html><html><body></body></html>', { url: 'http://localhost' });
+    for (const name of ['window', 'document', 'localStorage', 'CustomEvent', 'Event'] as const) {
+      Object.defineProperty(globalThis, name, { configurable: true, value: name === 'window' ? dom.window : dom.window[name] });
+    }
+    Object.defineProperty(globalThis, 'IS_REACT_ACT_ENVIRONMENT', { configurable: true, value: true });
+    const primary: AISession = {
+      id: 'closed-primary', title: 'Closed primary', agentId: 'catty',
+      scope: { type: scopeType, targetId: 'closed-target' },
+      createdAt: 1, updatedAt: 2, messages: [],
+    };
+    const diskOnly: AISession = {
+      ...primary, id: 'disk-only', title: 'Disk only', updatedAt: 1,
+      scope: { type: scopeType, targetId: 'another-closed-target' },
+    };
+    dom.window.localStorage.setItem(STORAGE_KEY_AI_SESSIONS, JSON.stringify([primary]));
+    dom.window.localStorage.setItem(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW, JSON.stringify([diskOnly.id]));
+    setLatestAISessionsSnapshot(null as unknown as AISession[]);
+    __resetBackupMirrorForTests();
+    const backups: string[] = [];
+    let reads = 0;
+    let resolveRead!: (backup: { ok: boolean; json: string }) => void;
+    Object.assign(dom.window, { netcatty: {
+      aiSessionsBackupWrite: async ({ json }: { json: string }) => { backups.push(json); return { ok: true }; },
+      aiSessionsBackupReadLatest: () => {
+        reads += 1;
+        return new Promise(resolve => { resolveRead = resolve; });
+      },
+    } });
+    let sessions: readonly AISession[] = [];
+    function Harness() {
+      const ai = useAIState();
+      sessions = useAISessionsStore().sessions;
+      // TerminalLayerSupport performs this cleanup on mount, while the disk
+      // backup IPC read can still be pending.
+      React.useEffect(() => { ai.cleanupOrphanedSessions(new Set()); }, [ai.cleanupOrphanedSessions]);
+      return null;
+    }
+    const container = document.createElement('div');
+    document.body.appendChild(container);
+    const root = createRoot(container);
+    try {
+      await act(async () => { root.render(React.createElement(Harness)); });
+      assert.equal(reads, 1);
+      assert.deepEqual(sessions, [{ ...primary, scopeDangling: true }]);
+      assert.deepEqual(JSON.parse(dom.window.localStorage.getItem(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW)!), [diskOnly.id]);
+      flushBackupMirror();
+      assert.deepEqual(backups, []);
+
+      await act(async () => { resolveRead({ ok: true, json: JSON.stringify([primary, diskOnly]) }); });
+      const expected = [primary, diskOnly].map(session => ({ ...session, scopeDangling: true }));
+      assert.deepEqual(sessions, expected);
+      assert.deepEqual(readSessionsFromStorage(), expected);
+      assert.equal(dom.window.localStorage.getItem(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW), null);
+      flushBackupMirror();
+      assert.deepEqual(JSON.parse(backups.at(-1)!), expected);
+    } finally {
+      await act(async () => { root.unmount(); });
+      __resetBackupMirrorForTests();
+      setLatestAISessionsSnapshot([]);
+      container.remove();
+      dom.window.close();
+    }
+  });
+}
+
+for (const mutation of ['rename', 'create', 'delete', 'delete-pending'] as const) {
+  test(`live ${mutation} preserves intended history across pending disk recovery`, async () => {
+    const dom = new JSDOM('<!doctype html><html><body></body></html>', { url: 'http://localhost' });
+    for (const name of ['window', 'document', 'localStorage', 'CustomEvent', 'Event'] as const) {
+      Object.defineProperty(globalThis, name, { configurable: true, value: name === 'window' ? dom.window : dom.window[name] });
+    }
+    Object.defineProperty(globalThis, 'IS_REACT_ACT_ENVIRONMENT', { configurable: true, value: true });
+    const primary: AISession = {
+      id: 'primary', title: 'Primary', agentId: 'catty', scope: { type: 'global' },
+      createdAt: 1, updatedAt: 2, messages: [],
+    };
+    const diskOnly = { ...primary, id: 'disk-only', updatedAt: 1 };
+    dom.window.localStorage.setItem(STORAGE_KEY_AI_SESSIONS, JSON.stringify([primary]));
+    dom.window.localStorage.setItem(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW, JSON.stringify([diskOnly.id]));
+    dom.window.localStorage.setItem(STORAGE_KEY_AI_ACTIVE_SESSION_MAP, JSON.stringify({ 'global:': diskOnly.id }));
+    setLatestAIActiveSessionMapSnapshot({ 'global:': diskOnly.id });
+    setLatestAISessionsSnapshot(null as unknown as AISession[]);
+    __resetBackupMirrorForTests();
+    const backups: string[] = [];
+    let resolveRead!: (backup: { ok: boolean; json: string }) => void;
+    Object.assign(dom.window, { netcatty: {
+      aiSessionsBackupWrite: async ({ json }: { json: string }) => { backups.push(json); return { ok: true }; },
+      aiSessionsBackupReadLatest: () => new Promise(resolve => { resolveRead = resolve; }),
+    } });
+    let ai!: ReturnType<typeof useAIState>;
+    let snapshot!: ReturnType<typeof useAISessionsStore>;
+    function Harness() {
+      ai = useAIState();
+      snapshot = useAISessionsStore();
+      return null;
+    }
+    const container = document.createElement('div');
+    document.body.appendChild(container);
+    const root = createRoot(container);
+    try {
+      await act(async () => { root.render(React.createElement(Harness)); });
+      assert.equal(snapshot.activeSessionIdMap['global:'], diskOnly.id);
+      await act(async () => {
+        if (mutation === 'rename') ai.updateSessionTitle(primary.id, 'Renamed before recovery');
+        else if (mutation === 'create') ai.createSession({ type: 'global' }, 'catty');
+        else ai.deleteSession(mutation === 'delete-pending' ? diskOnly.id : primary.id);
+      });
+      const liveBeforeRecovery = [...snapshot.sessions];
+      const expectedActiveId = mutation === 'create' ? liveBeforeRecovery[0].id
+        : mutation === 'delete-pending' ? null : diskOnly.id;
+      assert.equal(snapshot.activeSessionIdMap['global:'], expectedActiveId);
+      assert.deepEqual(readSessionsFromStorage(), liveBeforeRecovery);
+      const recoveryMarker = dom.window.localStorage.getItem(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW);
+      assert.deepEqual(recoveryMarker == null ? null : JSON.parse(recoveryMarker), mutation === 'delete-pending' ? null : [diskOnly.id]);
+      flushBackupMirror();
+      assert.deepEqual(backups.map(json => JSON.parse(json)), mutation === 'delete-pending' ? [liveBeforeRecovery] : []);
+
+      await act(async () => { resolveRead({ ok: true, json: JSON.stringify([primary, diskOnly]) }); });
+      const expected = mutation === 'delete-pending' ? liveBeforeRecovery : [...liveBeforeRecovery, diskOnly];
+      assert.deepEqual(snapshot.sessions, expected);
+      assert.deepEqual(readSessionsFromStorage(), expected);
+      assert.equal(dom.window.localStorage.getItem(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW), null);
+      flushBackupMirror();
+      assert.deepEqual(JSON.parse(backups.at(-1)!), expected);
+    } finally {
+      await act(async () => { root.unmount(); });
+      __resetBackupMirrorForTests();
+      setLatestAISessionsSnapshot([]);
+      setLatestAIActiveSessionMapSnapshot({});
+      container.remove();
+      dom.window.close();
+    }
+  });
+}
+
+test('count-cap eviction clears a loaded disk-only marker and resumes backup mirroring', () => {
+  const dom = new JSDOM('<!doctype html><html><body></body></html>', { url: 'http://localhost' });
+  for (const name of ['window', 'document', 'localStorage', 'CustomEvent', 'Event'] as const) {
+    Object.defineProperty(globalThis, name, { configurable: true, value: name === 'window' ? dom.window : dom.window[name] });
+  }
+  const source: AISession[] = Array.from({ length: 51 }, (_, index) => ({
+    id: `chat-${index}`, title: `Chat ${index}`, agentId: 'catty', scope: { type: 'global' },
+    createdAt: 1, updatedAt: 51 - index, messages: [],
+  }));
+  dom.window.localStorage.setItem(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW, JSON.stringify([source[50].id]));
+  const backups: string[] = [];
+  Object.assign(dom.window, { netcatty: { aiSessionsBackupWrite: async ({ json }: { json: string }) => {
+    backups.push(json);
+    return { ok: true };
+  } } });
+  __resetBackupMirrorForTests();
+  try {
+    assert.equal(writeSessionsForStorage(source), true);
+    assert.deepEqual(readSessionsFromStorage(), source.slice(0, 50));
+    assert.equal(dom.window.localStorage.getItem(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW), null);
+    flushBackupMirror();
+    assert.deepEqual(backups.map(json => JSON.parse(json)), [source.slice(0, 50)]);
+  } finally {
+    __resetBackupMirrorForTests();
+    dom.window.close();
+  }
+});
+
+for (const keepPrimary of [true, false]) {
+  test(`deletion clears disk-only recovery and remains authoritative (keep primary ${keepPrimary})`, async () => {
+    const dom = new JSDOM('<!doctype html><html><body></body></html>', { url: 'http://localhost' });
+    for (const name of ['window', 'document', 'localStorage', 'CustomEvent', 'Event'] as const) {
+      Object.defineProperty(globalThis, name, { configurable: true, value: name === 'window' ? dom.window : dom.window[name] });
+    }
+    Object.defineProperty(globalThis, 'IS_REACT_ACT_ENVIRONMENT', { configurable: true, value: true });
+    const primary: AISession = {
+      id: 'primary', title: 'Primary', agentId: 'catty', scope: { type: 'global' },
+      createdAt: 1, updatedAt: 2, messages: [],
+    };
+    dom.window.localStorage.setItem(STORAGE_KEY_AI_SESSIONS, JSON.stringify([primary]));
+    dom.window.localStorage.setItem(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW, JSON.stringify(['deleted-chat']));
+    const remaining = keepPrimary ? [primary] : [];
+    assert.equal(writeSessionsForStorage(remaining, { deletedSessionIds: ['deleted-chat'] }), true);
+    assert.equal(dom.window.localStorage.getItem(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW), null);
+    __resetBackupMirrorForTests();
+    setLatestAISessionsSnapshot(null as unknown as AISession[]);
+    let reads = 0;
+    Object.assign(dom.window, { netcatty: { aiSessionsBackupReadLatest: async () => {
+      reads += 1;
+      return { ok: true, json: JSON.stringify([primary, { ...primary, id: 'deleted-chat' }]) };
+    } } });
+    let sessions: readonly AISession[] = [];
+    function Harness() {
+      useAIState();
+      sessions = useAISessionsStore().sessions;
+      return null;
+    }
+    const container = document.createElement('div');
+    document.body.appendChild(container);
+    const root = createRoot(container);
+    try {
+      await act(async () => { root.render(React.createElement(Harness)); });
+      assert.equal(reads, 0);
+      assert.deepEqual(sessions, remaining);
+    } finally {
+      await act(async () => { root.unmount(); });
+      __resetBackupMirrorForTests();
+      setLatestAISessionsSnapshot([]);
+      container.remove();
+      dom.window.close();
+    }
+  });
+}

application/state/useAIState.ts

@@ -14,12 +14,15 @@ import {
   STORAGE_KEY_AI_RESPONSE_IDLE_TIMEOUT,
   STORAGE_KEY_AI_MAX_ITERATIONS,
   STORAGE_KEY_AI_SESSIONS,
+  STORAGE_KEY_AI_SESSIONS_OVERFLOW,
+  STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW,
   STORAGE_KEY_AI_ACTIVE_SESSION_MAP,
   STORAGE_KEY_AI_AGENT_MODEL_MAP,
   STORAGE_KEY_AI_AGENT_PROVIDER_MAP,
   STORAGE_KEY_AI_AGENT_THINKING_MAP,
   STORAGE_KEY_AI_WEB_SEARCH,
   STORAGE_KEY_AI_QUICK_MESSAGES,
+  STORAGE_KEY_CLOUD_SYNC_AI_SESSIONS,
 } from '../../infrastructure/config/storageKeys';
 import type { AIQuickMessage } from '../../infrastructure/ai/quickMessages';
 import { sanitizeQuickMessages } from '../../infrastructure/ai/quickMessages';
@@ -63,12 +66,18 @@ import {
   bumpDraftUploadGeneration,
   cleanupDeletedAIChatSessions,
   cleanupOrphanedAISessions,
+  latestAIActiveTargetIdsSnapshot,
   getAIBridge,
+  flushBackupMirror,
   getDraftUploadGeneration,
   latestAIActiveSessionMapSnapshot,
   latestAIDraftsByScopeSnapshot,
   latestAIPanelViewByScopeSnapshot,
   latestAISessionsSnapshot,
+  prepareRestoredSessions,
+  readSessionsFromStorage,
+  scheduleBackupMirror,
+  rebindActiveSessionMap,
   writeSessionsForStorage,
   setLatestAIActiveSessionMapSnapshot,
   setLatestAIDraftsByScopeSnapshot,
@@ -77,6 +86,12 @@ import {
   type DraftsByScope,
   type PanelViewByScope,
 } from './aiStateSnapshots';
+import {
+  isMissingOrCorruptSessionsStore,
+  parseSessionsStore,
+  mergeImportedSessions,
+  parseBackupSessions,
+} from './aiSessionsBackup';
 import { AI_STATE_CHANGED_EVENT, emitAIStateChanged } from './aiStateEvents';
 import {
   persistCommandBlocklistSetting,
@@ -168,9 +183,82 @@ export function useAIState() {
   // ── Sessions ──
   const [sessions, setSessionsRaw] = useState<AISession[]>(() =>
     latestAISessionsSnapshot
-      ?? localStorageAdapter.read<AISession[]>(STORAGE_KEY_AI_SESSIONS)
-      ?? []
+      ?? readSessionsFromStorage()
   );
+  // An explicit empty array is authoritative, even if the backup is stale.
+  // Disk-only overflow IDs also permit recovery, without reviving deleted chats.
+  useEffect(() => {
+    window.addEventListener('beforeunload', flushBackupMirror);
+    return () => window.removeEventListener('beforeunload', flushBackupMirror);
+  }, []);
+  useEffect(() => {
+    const liveRaw = localStorageAdapter.readString(STORAGE_KEY_AI_SESSIONS);
+    const liveStore = parseSessionsStore(liveRaw);
+    const liveSessions = readSessionsFromStorage();
+    const diskOnlyRecovery = (localStorageAdapter.read<string[]>(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW)?.length ?? 0) > 0;
+    if (!diskOnlyRecovery && (liveStore.valid || liveSessions.length > 0)) {
+      if (liveSessions.length > 0) scheduleBackupMirror(JSON.stringify(liveSessions));
+      return;
+    }
+    if (!diskOnlyRecovery && latestAISessionsSnapshot && latestAISessionsSnapshot.length > 0) return;
+    const bridge = getAIBridge();
+    if (!bridge?.aiSessionsBackupReadLatest) return;
+    let cancelled = false;
+    const canRestore = () => diskOnlyRecovery
+      ? (localStorageAdapter.read<string[]>(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW)?.length ?? 0) > 0
+      : isMissingOrCorruptSessionsStore(localStorageAdapter.readString(STORAGE_KEY_AI_SESSIONS))
+        && readSessionsFromStorage().length === 0
+        && (latestAISessionsSnapshot?.length ?? 0) === 0
+        && sessionsRef.current.length === 0;
+    void (async () => {
+      try {
+        if (!canRestore()) return;
+        const backup = await bridge.aiSessionsBackupReadLatest?.();
+        if (cancelled || !backup?.ok) return;
+        // Re-check after the async gap so live mutations and deletions win.
+        if (!canRestore()) return;
+        const backupSessions = parseBackupSessions(backup.json);
+        if (!backupSessions) return;
+        const diskOnlyIds = new Set(localStorageAdapter.read<string[]>(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW) ?? []);
+        const recovered = diskOnlyRecovery
+          ? mergeImportedSessions(
+            backupSessions.filter(session => diskOnlyIds.has(session.id)),
+            latestAISessionsSnapshot ?? readSessionsFromStorage(),
+          )
+          : backupSessions;
+        const syncEnabled = !!localStorageAdapter.read<{ enabled?: boolean }>(STORAGE_KEY_CLOUD_SYNC_AI_SESSIONS)?.enabled;
+        const restored = prepareRestoredSessions(recovered, syncEnabled);
+        if (restored.length === 0) return;
+        // Apply restore synchronously (not inside a setState updater). A
+        // deferred updater would leave didRestore false and skip dangling
+        // marking even when the records later land in React state.
+        setLatestAISessionsSnapshot(restored);
+        writeSessionsForStorage(restored);
+        emitAIStateChanged(STORAGE_KEY_AI_SESSIONS);
+        // Restore does not change live terminals/workspaces, so the orphan-
+        // cleanup effect will not run. Reuse the last known live target set
+        // (empty is valid: nothing live) so chats bound to missing scopes
+        // become dangling and /chats can offer /rebind.
+        cleanupOrphanedAISessions(latestAIActiveTargetIdsSnapshot);
+        const nextSessions = latestAISessionsSnapshot ?? restored;
+        sessionsRef.current = nextSessions;
+        setSessionsRaw(nextSessions);
+        setActiveSessionIdMapRaw(
+          latestAIActiveSessionMapSnapshot
+            ?? localStorageAdapter.read<Record<string, string | null>>(STORAGE_KEY_AI_ACTIVE_SESSION_MAP)
+            ?? {},
+        );
+        console.info(
+          `[AIState] Restored ${restored.length} AI session(s) from the disk backup.`,
+        );
+      } catch {
+        // Backup restore must never break startup.
+      }
+    })();
+    return () => {
+      cancelled = true;
+    };
+  }, []);
   // Ref that always holds the latest sessions for use inside debounced callbacks
   const sessionsRef = useRef(sessions);
   useEffect(() => {
@@ -245,6 +333,11 @@ export function useAIState() {
 
   useEffect(() => {
     const validSessionIds = new Set<string>(sessions.map((session) => session.id));
+    // Disk-only chats may not have arrived from the startup backup read yet.
+    // Keep their active pointers and panel views until recovery or deletion.
+    for (const id of localStorageAdapter.read<string[]>(STORAGE_KEY_AI_SESSIONS_DISK_OVERFLOW) ?? []) {
+      validSessionIds.add(id);
+    }
     let changed = false;
     const nextActiveSessionIdMap: Record<string, string | null> = {};
 
@@ -464,7 +557,9 @@ export function useAIState() {
   useEffect(() => {
     const handleStorage = (e: StorageEvent) => {
       try {
-        switch (e.key) {
+        const key = e.key === STORAGE_KEY_AI_SESSIONS_OVERFLOW || e.key?.startsWith(`${STORAGE_KEY_AI_SESSIONS_OVERFLOW}_`)
+          ? STORAGE_KEY_AI_SESSIONS : e.key;
+        switch (key) {
           case STORAGE_KEY_AI_PROVIDERS: {
             const parsed = localStorageAdapter.read<ProviderConfig[]>(STORAGE_KEY_AI_PROVIDERS);
             if (parsed != null && !Array.isArray(parsed)) {
@@ -556,7 +651,7 @@ export function useAIState() {
             break;
           }
           case STORAGE_KEY_AI_SESSIONS: {
-            const nextSessions = localStorageAdapter.read<AISession[]>(STORAGE_KEY_AI_SESSIONS) ?? [];
+            const nextSessions = readSessionsFromStorage();
             setLatestAISessionsSnapshot(nextSessions);
             setSessionsRaw(nextSessions);
             break;
@@ -598,8 +693,7 @@ export function useAIState() {
         case STORAGE_KEY_AI_SESSIONS:
           setSessionsRaw(
             latestAISessionsSnapshot
-              ?? localStorageAdapter.read<AISession[]>(STORAGE_KEY_AI_SESSIONS)
-              ?? [],
+              ?? readSessionsFromStorage(),
           );
           return;
         case STORAGE_KEY_AI_ACTIVE_SESSION_MAP:
@@ -651,8 +745,8 @@ export function useAIState() {
   }, []);
 
   // ── Session CRUD ──
-  const persistSessions = useCallback((next: AISession[]) => {
-    writeSessionsForStorage(next);
+  const persistSessions = useCallback((next: AISession[], deletedSessionIds?: readonly string[]) => {
+    writeSessionsForStorage(next, { deletedSessionIds });
   }, []);
 
   // Debounced version of persistSessions for high-frequency updates (e.g. streaming)
@@ -797,7 +891,7 @@ export function useAIState() {
     setSessionsRaw(prev => {
       const next = prev.filter(s => s.id !== sessionId);
       setLatestAISessionsSnapshot(next);
-      persistSessions(next);
+      persistSessions(next, [sessionId]);
       return next;
     });
     if (scopeKey) {
@@ -841,7 +935,7 @@ export function useAIState() {
         return !(s.scope.type === scopeType && s.scope.targetId === targetId);
       });
       setLatestAISessionsSnapshot(next);
-      persistSessions(next);
+      persistSessions(next, removedSessionIds);
       return next;
     });
     const scopeKey = `${scopeType}:${targetId}`;
@@ -866,6 +960,102 @@ export function useAIState() {
     });
   }, [persistSessions]);
 
+  // Issue #4015 R2: rebind a dangling chat to the panel's current scope.
+  // Rewrites `scope`, clears the dangling marker and makes the chat the
+  // active session of its new scope so it shows in the scoped history again.
+  const rebindSessionScope = useCallback((
+    sessionId: string,
+    scope: { type: 'terminal' | 'workspace'; targetId: string; hostIds?: string[] },
+  ) => {
+    const scopeKey = `${scope.type}:${scope.targetId}`;
+    setSessionsRaw(prev => {
+      const next = prev.map(s => {
+        if (s.id !== sessionId) return s;
+        const { scopeDangling: _cleared, ...rest } = s;
+        // Replace scope entirely (including hostIds) so history matching follows
+        // the destination terminal/workspace rather than the chat's old host.
+        const nextScope: AISession['scope'] = {
+          type: scope.type,
+          targetId: scope.targetId,
+        };
+        if (scope.hostIds && scope.hostIds.length > 0) {
+          nextScope.hostIds = [...scope.hostIds];
+        }
+        return {
+          ...rest,
+          scope: nextScope,
+          updatedAt: Date.now(),
+        } as AISession;
+      });
+      setLatestAISessionsSnapshot(next);
+      persistSessions(next);
+      return next;
+    });
+    // Drop stale pointers that still reference this chat under its previous
+    // scope key, then restore the active pointer for the new scope.
+    // Compute + persist inside the updater so a deferred React setState still
+    // writes the cleaned map (outer capture would stay null and skip persist).
+    setActiveSessionIdMapRaw(prev => {
+      const next = rebindActiveSessionMap(prev, sessionId, scopeKey);
+      setLatestAIActiveSessionMapSnapshot(next);
+      localStorageAdapter.write(STORAGE_KEY_AI_ACTIVE_SESSION_MAP, next);
+      emitAIStateChanged(STORAGE_KEY_AI_ACTIVE_SESSION_MAP);
+      return next;
+    });
+    // Open the rebound chat in this panel; active-map alone loses to an
+    // explicit draft/session panelView that still points elsewhere.
+    setPanelViewByScope((prev) => setSessionView(prev, scopeKey, sessionId));
+  }, [persistSessions, setPanelViewByScope]);
+
+  // Manual durability escape hatch (issue #4015 follow-up): export the
+  // current store to a user-chosen JSON file, or import one back in.
+  // Import is an explicit action, so it may overwrite the live store.
+  const exportSessionsBackup = useCallback(async (): Promise<string | null> => {
+    const bridge = getAIBridge();
+    if (!bridge?.aiSessionsBackupExport) return null;
+    const result = await bridge.aiSessionsBackupExport({
+      json: JSON.stringify(sessionsRef.current),
+    });
+    return result?.success ? (result.filePath ?? '') : null;
+  }, []);
+
+  const importSessionsBackup = useCallback(async (): Promise<number> => {
+    const bridge = getAIBridge();
+    if (!bridge?.aiSessionsBackupImport) return 0;
+    const result = await bridge.aiSessionsBackupImport();
+    if (!result?.success || !result.json) return 0;
+    const imported = parseBackupSessions(result.json);
+    if (!imported || imported.length === 0) return 0;
+    // Merge synchronously against the live ref so orphan cleanup sees the
+    // imported chats even if React would defer a setState updater.
+    const syncEnabled = !!localStorageAdapter.read<{ enabled?: boolean }>(STORAGE_KEY_CLOUD_SYNC_AI_SESSIONS)?.enabled;
+    const next = prepareRestoredSessions(mergeImportedSessions(sessionsRef.current, imported), syncEnabled);
+    if (!writeSessionsForStorage(next)) return 0;
+    // Local readback can omit disk-only overflow chats. Keep the complete
+    // prepared history live so cleanup and later writes retain those chats.
+    const importedIds = new Set(imported.map(session => session.id));
+    sessionsRef.current = next;
+    setLatestAISessionsSnapshot(next);
+    setSessionsRaw(next);
+    emitAIStateChanged(STORAGE_KEY_AI_SESSIONS);
+    // Import does not change live terminals/workspaces, so the orphan-cleanup
+    // effect will not run. Reuse the last known live target set (empty is
+    // valid: nothing live) to mark chats bound to missing scopes as dangling
+    // so /chats can offer /rebind.
+    cleanupOrphanedAISessions(latestAIActiveTargetIdsSnapshot);
+    const nextSessions =
+      latestAISessionsSnapshot
+      ?? next;
+    sessionsRef.current = nextSessions;
+    setSessionsRaw(nextSessions);
+    setActiveSessionIdMapRaw(
+      latestAIActiveSessionMapSnapshot
+        ?? localStorageAdapter.read<Record<string, string | null>>(STORAGE_KEY_AI_ACTIVE_SESSION_MAP)
+        ?? {},
+    );
+    return nextSessions.filter(session => importedIds.has(session.id)).length;
+  }, []);
+
   const updateSessionExternalSessionId = useCallback((sessionId: string, externalSessionId: string | undefined) => {
     setSessionsRaw(prev => {
       const next = prev.map(s => (
@@ -879,16 +1069,17 @@ export function useAIState() {
     });
   }, [debouncedPersistSessions]);
 
-  // Maximum messages per session to prevent unbounded memory growth
+  // Local-only retention. Synced history must match the full-history storage policy.
   const MAX_MESSAGES_PER_SESSION = 500;
 
   const addMessageToSession = useCallback((sessionId: string, message: ChatMessage) => {
+    const syncEnabled = localStorageAdapter.read<{ enabled?: boolean }>(STORAGE_KEY_CLOUD_SYNC_AI_SESSIONS)?.enabled === true;
     setSessionsRaw(prev => {
       const next = prev.map(s => {
         if (s.id !== sessionId) return s;
         let msgs = [...s.messages, message];
-        // Trim oldest messages if exceeding limit (keep system messages)
-        if (msgs.length > MAX_MESSAGES_PER_SESSION) {
+        // Dropping synced prefixes makes the next cloud merge add them back.
+        if (!syncEnabled && msgs.length > MAX_MESSAGES_PER_SESSION) {
           const systemMsgs = msgs.filter(m => m.role === 'system');
           const nonSystemMsgs = msgs.filter(m => m.role !== 'system');
           const dropped = nonSystemMsgs.length - (MAX_MESSAGES_PER_SESSION - systemMsgs.length);
@@ -1134,8 +1325,7 @@ export function useAIState() {
 
     const nextSessions =
       latestAISessionsSnapshot
-      ?? localStorageAdapter.read<AISession[]>(STORAGE_KEY_AI_SESSIONS)
-      ?? [];
+      ?? readSessionsFromStorage();
     sessionsRef.current = nextSessions;
     setSessionsRaw(nextSessions);
     setActiveSessionIdMapRaw(
@@ -1187,8 +1377,7 @@ export function useAIState() {
       ?? {};
     const currentSessions =
       latestAISessionsSnapshot
-      ?? localStorageAdapter.read<AISession[]>(STORAGE_KEY_AI_SESSIONS)
-      ?? [];
+      ?? readSessionsFromStorage();
     const currentPanelViewByScope = latestAIPanelViewByScopeSnapshot ?? {};
     const result = handoffDissolvedWorkspaceAIScope({
       activeSessionIdMap: currentMap,
@@ -1233,8 +1422,7 @@ export function useAIState() {
       ?? {};
     const currentSessions =
       latestAISessionsSnapshot
-      ?? localStorageAdapter.read<AISession[]>(STORAGE_KEY_AI_SESSIONS)
-      ?? [];
+      ?? readSessionsFromStorage();
     const result = retargetWorkspaceActiveChatAfterMemberLoss({
       activeSessionIdMap: currentMap,
       sessions: currentSessions,
@@ -1370,6 +1558,9 @@ export function useAIState() {
     deleteSession,
     deleteSessionsByTarget,
     updateSessionTitle,
+    rebindSessionScope,
+    exportSessionsBackup,
+    importSessionsBackup,
     updateSessionExternalSessionId,
     addMessageToSession,
     updateLastMessage,
@@ -1432,6 +1623,9 @@ export function useAIState() {
     deleteSession,
     deleteSessionsByTarget,
     updateSessionTitle,
+    rebindSessionScope,
+    exportSessionsBackup,
+    importSessionsBackup,
     updateSessionExternalSessionId,
     addMessageToSession,
     updateLastMessage,

application/state/useActiveChromeTheme.test.ts

@@ -11,6 +11,10 @@ import {
 } from "./useActiveChromeTheme.ts";
 import { TERMINAL_THEMES } from "../../infrastructure/config/terminalThemes.ts";
 import { readFileSync } from "node:fs";
+import {
+  getSettingsChromeSnapshot,
+  publishSettingsChromeSnapshot,
+} from "./settingsChromeStore.ts";
 
 function createInlineStyle() {
   const values = new Map<string, string>();
@@ -98,6 +102,60 @@ test("syncActiveChromeTheme skips surface refresh when the active theme fingerpr
   }
 });
 
+for (const preference of ["system", "light", "dark"] as const) {
+  for (const chromeType of ["light", "dark"] as const) {
+    test(`syncActiveChromeTheme uses ${preference === "system" ? "system" : chromeType} native theme for ${preference} preference and ${chromeType} chrome`, () => {
+      const globals = globalThis as typeof globalThis & { document?: Document; window?: Window };
+      const originalDocument = globals.document;
+      const originalWindow = globals.window;
+      const originalSnapshot = getSettingsChromeSnapshot();
+      const theme = TERMINAL_THEMES.find((candidate) => candidate.type === chromeType);
+      assert.ok(theme);
+      const themeCalls: string[] = [];
+      const backgroundCalls: string[] = [];
+      globals.document = {
+        documentElement: {
+          dataset: {},
+          classList: { remove: () => {}, add: () => {} },
+          removeAttribute: () => {},
+        },
+        getElementById: () => null,
+        createElement: () => ({}),
+        head: { appendChild: () => {} },
+        querySelector: () => null,
+      } as unknown as Document;
+      globals.window = {
+        netcatty: {
+          setTheme: (value: string) => themeCalls.push(value),
+          setBackgroundColor: (value: string) => backgroundCalls.push(value),
+        },
+      } as unknown as Window & typeof globalThis;
+
+      try {
+        publishSettingsChromeSnapshot({ ...originalSnapshot, theme: preference });
+        syncActiveChromeTheme(theme, () => {
+          throw new Error("app theme should not be restored for an active chrome theme");
+        });
+
+        assert.deepEqual(themeCalls, [preference === "system" ? "system" : chromeType]);
+        assert.deepEqual(backgroundCalls, [theme.colors.background]);
+      } finally {
+        publishSettingsChromeSnapshot(originalSnapshot);
+        if (originalDocument) {
+          globals.document = originalDocument;
+        } else {
+          delete globals.document;
+        }
+        if (originalWindow) {
+          globals.window = originalWindow;
+        } else {
+          delete globals.window;
+        }
+      }
+    });
+  }
+}
+
 test("active chrome theme foreground uses contrast calculation", () => {
   const source = readFileSync(new URL("./useActiveChromeTheme.ts", import.meta.url), "utf8");
 

application/state/useActiveChromeTheme.ts

@@ -1,6 +1,6 @@
 import { pluginThemeRegistry } from '../../infrastructure/config/pluginThemeRegistry';
 import { usePluginThemeRevision } from './usePluginThemeRuntime';
-import { useSettingsChromeStore } from './settingsChromeStore';
+import { getSettingsChromeSnapshot, useSettingsChromeStore } from './settingsChromeStore';
 import { useLayoutEffect, useRef } from "react";
 import type { TerminalTheme } from "../../domain/models";
 import {
@@ -239,7 +239,9 @@ function applyActiveChromeTheme(theme: TerminalTheme) {
 function refreshActiveChromeThemeSurfaces(theme: TerminalTheme) {
   const targetClass = theme.type === "dark" ? "dark" : "light";
   if (typeof window !== "undefined") {
-    netcattyBridge.get()?.setTheme?.(targetClass);
+    // Preserve OS preference events instead of locking nativeTheme to the chrome type.
+    const themeSource = getSettingsChromeSnapshot().theme === "system" ? "system" : targetClass;
+    netcattyBridge.get()?.setTheme?.(themeSource);
     netcattyBridge.get()?.setBackgroundColor?.(theme.colors.background);
   }
   applyTopTabsChromeThemeVars(theme);

application/state/useAppLockRuntime.test.ts

@@ -92,3 +92,21 @@ test("selectPreferredRuntimeAppLockState prefers initialized state when versions
     current,
   );
 });
+
+test("selectPreferredRuntimeAppLockState keeps the current object when a resync changes nothing", () => {
+  const current = normalizeRuntimeAppLockState({
+    initialized: true,
+    locked: false,
+    reason: null,
+    version: 4,
+    lastUnlockedAt: 1000,
+    lastActivityAt: 2000,
+  });
+  const resynced = normalizeRuntimeAppLockState({ ...current });
+  assert.notEqual(resynced, current);
+  // Window focus resyncs must not hand React a new state object.
+  assert.equal(selectPreferredRuntimeAppLockState(current, resynced), current);
+
+  const changed = normalizeRuntimeAppLockState({ ...current, locked: true, reason: "idle" });
+  assert.equal(selectPreferredRuntimeAppLockState(current, changed), changed);
+});

application/state/useAppLockRuntime.ts

@@ -43,7 +43,20 @@ export function selectPreferredRuntimeAppLockState(
   if (incoming.version < current.version) return current;
   if (incoming.initialized && !current.initialized) return incoming;
   if (!incoming.initialized && current.initialized) return current;
-  return incoming;
+  // Every window focus/visibility change resyncs; keep the current object when
+  // nothing changed so the gate (and the provider tree under it) does not
+  // re-render.
+  return isSameRuntimeAppLockState(current, incoming) ? current : incoming;
+}
+
+function isSameRuntimeAppLockState(left: RuntimeAppLockState, right: RuntimeAppLockState): boolean {
+  return left.initialized === right.initialized
+    && left.locked === right.locked
+    && left.reason === right.reason
+    && left.version === right.version
+    && left.lastLockedAt === right.lastLockedAt
+    && left.lastUnlockedAt === right.lastUnlockedAt
+    && left.lastActivityAt === right.lastActivityAt;
 }
 
 export function useAppLockRuntime(

application/state/useAppLockState.ts

@@ -1,4 +1,4 @@
-import { useCallback, useEffect, useMemo, useState } from 'react';
+import { useCallback, useEffect, useMemo, useRef, useState } from 'react';
 
 import {
   normalizeAppLockSettings,
@@ -131,6 +131,8 @@ export function createOptimisticUnlockedRuntimeState(
   };
 }
 
+
+export const APP_LOCK_ACTIVITY_REPORT_INTERVAL_MS = 1000;
 export function useAppLockState(settings: AppLockSettings) {
   const normalizedSettings = useMemo(() => normalizeAppLockSettings(settings), [settings]);
   const systemUnlockRefreshKey = `${normalizedSettings.enabled}:${normalizedSettings.systemUnlockEnabled}:${Boolean(normalizedSettings.passwordVerifier)}`;
@@ -160,8 +162,14 @@ export function useAppLockState(settings: AppLockSettings) {
     void bridge?.setAppLockRuntimeLocked?.(reason);
   }, [bridge, normalizedSettings]);
 
+  // Activity only resets a minutes-long idle timer; one report per second is
+  // enough instead of an IPC per keystroke, wheel tick and pointer event.
+  const lastActivityReportAtRef = useRef(0);
   const recordActivity = useCallback(() => {
     if (effectiveRuntimeState.locked) return;
+    const now = Date.now();
+    if (now - lastActivityReportAtRef.current < APP_LOCK_ACTIVITY_REPORT_INTERVAL_MS) return;
+    lastActivityReportAtRef.current = now;
     void bridge?.reportAppLockActivity?.();
   }, [bridge, effectiveRuntimeState.locked]);
 
@@ -249,7 +257,9 @@ export function useAppLockState(settings: AppLockSettings) {
     void refreshSystemUnlockStatus();
   }, [refreshSystemUnlockStatus, systemUnlockRefreshKey]);
 
-  return {
+  // Stable identity: AppLockGate passes this to <App>, whose provider tree
+  // re-renders whenever it changes.
+  return useMemo(() => ({
     initialized: effectiveRuntimeState.initialized,
     locked: effectiveRuntimeState.locked,
     lockReason: effectiveRuntimeState.reason,
@@ -261,5 +271,17 @@ export function useAppLockState(settings: AppLockSettings) {
     reset,
     recordActivity,
     resync: refreshRuntimeState,
-  };
+  }), [
+    effectiveRuntimeState.initialized,
+    effectiveRuntimeState.locked,
+    effectiveRuntimeState.reason,
+    lockNow,
+    unlock,
+    unlockWithSystemAuth,
+    systemUnlockStatus,
+    refreshSystemUnlockStatus,
+    reset,
+    recordActivity,
+    refreshRuntimeState,
+  ]);
 }

application/state/useEmbeddedPluginView.ts

@@ -1,119 +0,0 @@
-import { useEffect, useRef, useState } from 'react';
-import { PluginViewLifecycleController, type HostedPluginViewState } from './pluginViewLifecycle';
-import { resolvePluginViewWindowScope } from './pluginViewScopes';
-import { isPluginViewOccluded } from './pluginViewOcclusion';
-import type { UsePluginContributionsResult } from './usePluginContributions';
-
-type ViewAdapter = Pick<UsePluginContributionsResult, 'openView' | 'closeView' | 'focusView' | 'setViewBounds' | 'setViewVisibility' | 'onViewClosed' | 'onViewFocused'>;
-
-/** Host-owned mounting only. No plugin router, DOM, session or vault data API. */
-export function useEmbeddedPluginView({ viewId, version, slot, active, context, adapter, subscribeHidden, unavailable, focused, focusOnReveal = false }: {
-  viewId: string;
-  version: string;
-  slot: string;
-  active: boolean;
-  context: Record<string, unknown>;
-  adapter: ViewAdapter;
-  subscribeHidden(listener: () => void): () => void;
-  unavailable(): void;
-  focused?(): void;
-  focusOnReveal?: boolean;
-}) {
-  const mountRef = useRef<HTMLDivElement>(null);
-  const [loading, setLoading] = useState(true);
-  const adapterRef = useRef(adapter);
-  const unavailableRef = useRef(unavailable);
-  const focusedRef = useRef(focused);
-  const revealFocusRef = useRef(focusOnReveal);
-  const requestFocusRef = useRef<() => void>(() => {});
-  revealFocusRef.current = focusOnReveal;
-  focusedRef.current = focused;
-  adapterRef.current = adapter;
-  unavailableRef.current = unavailable;
-  useEffect(() => {
-    const mount = mountRef.current;
-    if (!active || !mount) return;
-    let cancelled = false;
-    const lifecycle = new PluginViewLifecycleController<HostedPluginViewState>();
-    const instanceId = crypto.randomUUID();
-    const scopeId = resolvePluginViewWindowScope({ pathname: window.location.pathname,
-      search: window.location.search, hash: `${window.location.hash}|plugin-slot:${slot}` });
-    const { openView, closeView, focusView, setViewBounds, setViewVisibility, onViewClosed, onViewFocused } = adapterRef.current;
-    const close = () => {
-      if (cancelled) return;
-      cancelled = true;
-      lifecycle.markViewClosed(viewId);
-      void closeView(instanceId).catch(() => {});
-    };
-    const failCurrent = () => {
-      if (cancelled) return;
-      close();
-      unavailableRef.current();
-    };
-    const unsubscribe = onViewClosed((event) => {
-      lifecycle.handleHostClose(event.instanceId);
-      if (event.instanceId === instanceId && !cancelled) {
-        close();
-        unavailableRef.current();
-      }
-    });
-    const stopOnHide = subscribeHidden(close);
-    const stopOnFocus = onViewFocused((event) => {
-      if (!cancelled && event.instanceId === instanceId) focusedRef.current?.();
-    });
-    const bounds = () => {
-      const rect = mount.getBoundingClientRect();
-      return { x: Math.round(rect.x), y: Math.round(rect.y), width: Math.max(1, Math.round(rect.width)), height: Math.max(1, Math.round(rect.height)) };
-    };
-    let opened = false;
-    let lastBounds = '';
-    let visible = false;
-    const focus = () => {
-      if (!cancelled && opened && visible && revealFocusRef.current && !isPluginViewOccluded(mount)) void focusView(instanceId).catch(() => {});
-    };
-    requestFocusRef.current = focus;
-    const updateVisibility = () => {
-      if (!opened || cancelled) return;
-      const rect = mount.getBoundingClientRect();
-      const next = rect.width > 0 && rect.height > 0 && !isPluginViewOccluded(mount);
-      if (visible === next) return;
-      visible = next;
-      void setViewVisibility(instanceId, next).then(() => { if (next) focus(); }).catch(failCurrent);
-    };
-    const resize = () => {
-      if (opened && !cancelled) {
-        const next = bounds();
-        const key = JSON.stringify(next);
-        if (key !== lastBounds) { lastBounds = key; void setViewBounds(instanceId, next).catch(failCurrent); }
-      }
-      updateVisibility();
-    };
-    const observer = typeof ResizeObserver === 'undefined' ? null : new ResizeObserver(resize);
-    observer?.observe(mount);
-    const mutations = new MutationObserver(resize);
-    mutations.observe(document.body, { childList: true, subtree: true, attributes: true,
-      attributeFilter: ['class', 'style', 'hidden', 'inert', 'role', 'aria-modal', 'aria-hidden', 'data-state', 'data-app-lock-overlay', 'data-radix-popper-content-wrapper', 'data-native-view-occluder'] });
-    window.addEventListener('resize', resize);
-    document.addEventListener('scroll', resize, true);
-    setLoading(true);
-    const opening = lifecycle.beginOpen({ viewKey: viewId });
-    void openView({ viewId, instanceId, scopeId, bounds: bounds(), context }).then(async (result) => {
-      if (cancelled || lifecycle.shouldCloseOpen(opening) || lifecycle.consumeHostClose(result.instanceId)) {
-        await closeView(result.instanceId);
-        return;
-      }
-      opened = true;
-      lifecycle.setCurrent({ id: result.instanceId, viewId, scopeId, retainContextWhenHidden: false });
-      resize();
-      setLoading(false);
-    }).catch(() => {
-      if (!cancelled) { close(); unavailableRef.current(); }
-    }).finally(() => lifecycle.finishOpen({ token: opening, viewKey: viewId }));
-    return () => {
-      close(); unsubscribe(); stopOnHide(); stopOnFocus(); observer?.disconnect(); mutations.disconnect();
-      window.removeEventListener('resize', resize); document.removeEventListener('scroll', resize, true);
-    };
-  }, [active, context, slot, subscribeHidden, version, viewId]);
-  useEffect(() => { if (focusOnReveal) requestFocusRef.current(); }, [focusOnReveal]);
-  return { mountRef, loading };
-}

application/state/useHostDrawnPluginView.ts

@@ -0,0 +1,42 @@
+import { useCallback, useEffect, useRef, useState } from 'react';
+import { netcattyBridge } from '../../infrastructure/services/netcattyBridge';
+import { resolvePluginViewWindowScope } from './pluginViewScopes';
+import { pluginViewSessions, type PluginViewSnapshot } from './pluginViewSession';
+import type { HostDrawnViewEvent } from '@netcatty/plugin-contract';
+
+const initial = (): PluginViewSnapshot => ({ tree: { children: [] }, css: '', loading: true, error: false, settled: true });
+export function useHostDrawnPluginView({ viewId, version, slot, active, context, subscribeHidden, unavailable }: {
+  viewId: string; version: string; slot: string; active: boolean; context: Record<string, unknown>;
+  subscribeHidden(listener: () => void): () => void; unavailable(): void;
+}) {
+  const contextKey = JSON.stringify(context);
+  const key = JSON.stringify([viewId, version, slot, contextKey]);
+  const [state, setState] = useState<{ key: string; snapshot: PluginViewSnapshot }>({ key: '', snapshot: initial() });
+  const [hidden, setHidden] = useState(false);
+  const unavailableRef = useRef(unavailable); unavailableRef.current = unavailable;
+  const sessionRef = useRef<{ key: string; image(path: string): Promise<string>; send(event: HostDrawnViewEvent): void } | null>(null);
+  useEffect(() => {
+    if (!active) return;
+    const bridge = netcattyBridge.get();
+    if (!bridge) { unavailableRef.current(); return; }
+    const scopeId = resolvePluginViewWindowScope({ pathname: window.location.pathname, search: window.location.search, hash: `${window.location.hash}|plugin-slot:${slot}` });
+    try {
+      const session = pluginViewSessions.acquire(JSON.stringify([scopeId, key]), bridge, { viewId, scopeId, context: JSON.parse(contextKey) });
+      const update = () => { const snapshot = session.getSnapshot(); setState({ key, snapshot }); if (snapshot.error) unavailableRef.current(); };
+      const stop = session.subscribe(update); update(); setHidden(false);
+      sessionRef.current = { key, send: session.send, image: session.image };
+      const stopHidden = subscribeHidden(() => { sessionRef.current = null; setHidden(true); });
+      return () => { sessionRef.current = null; stopHidden(); stop(); session.release(); };
+    } catch { unavailableRef.current(); }
+  }, [active, contextKey, key, slot, subscribeHidden, viewId]);
+  const loadImage = useCallback((path: string) => {
+    const session = sessionRef.current;
+    return active && session?.key === key ? session.image(path) : Promise.reject(new Error('Plugin view unavailable'));
+  }, [active, key]);
+  const sendEvent = useCallback((event: HostDrawnViewEvent) => {
+    const session = sessionRef.current; if (active && session?.key === key) session.send(event);
+  }, [active, key]);
+  // A newly selected plugin must never receive values from the previous tree,
+  // even during the render before effect cleanup and the next activation.
+  return { ...(state.key === key ? state.snapshot : initial()), visible: active && !hidden, loadImage, sendEvent };
+}

application/state/useMonitorDiskGroups.ts

@@ -0,0 +1,17 @@
+import { useState } from "react";
+import { buildMonitorDiskListLayout, type MonitorDiskListStats } from "../../domain/monitorDisks";
+
+/** Volatile per-host disclosure preference; capacity alerts always force it open. */
+export function useMonitorDiskGroups() {
+  const [expandedHosts, setExpandedHosts] = useState<ReadonlySet<string>>(() => new Set());
+  return {
+    layoutFor: (hostId: string, stats?: MonitorDiskListStats | null) =>
+      buildMonitorDiskListLayout(stats, expandedHosts.has(hostId)),
+    toggle: (hostId: string) => setExpandedHosts(previous => {
+      const next = new Set(previous);
+      if (next.has(hostId)) next.delete(hostId);
+      else next.add(hostId);
+      return next;
+    }),
+  };
+}

application/state/useMonitorRuntime.ts

@@ -13,6 +13,7 @@ import { useMonitorPanels } from "./monitorPanelsStorage";
 import {
   monitorActions,
   getMonitorHistoryCursor,
+  isIdleMonitorSnapshot,
   publishMonitorSnapshot,
   publishMonitorUnavailable,
 } from "./monitorRuntimeStore";
@@ -157,16 +158,24 @@ export function useMonitorRuntime() {
     isInitialized,
     retryVersion,
   ]);
+  // Poll every second while anything is monitored (here or in another window);
+  // otherwise only every 10 s to notice monitors started elsewhere. Starting a
+  // panel here publishes demand and reads a snapshot immediately, and flipping
+  // `hasRunningPanels` restarts this loop at the fast cadence.
+  const hasRunningPanels = running.size > 0;
   useEffect(() => {
     const bridge = netcattyBridge.get();
     let disposed = false;
     let pending = false;
+    let remoteRunning = false;
+    let timer: ReturnType<typeof setTimeout> | null = null;
     const poll = async () => {
       if (pending || !bridge?.monitorSnapshot) return;
       pending = true;
       try {
         const snapshot = await bridge.monitorSnapshot(getMonitorHistoryCursor());
         if (disposed) return;
+        remoteRunning = !isIdleMonitorSnapshot(snapshot);
         if (
           (epoch.current !== null && epoch.current !== snapshot.epoch) ||
           (runtimeId.current !== null &&
@@ -186,13 +195,16 @@ export function useMonitorRuntime() {
         pending = false;
       }
     };
-    void poll();
-    const timer = setInterval(() => {
-      void poll();
-    }, 1000);
+    const schedule = () => {
+      if (disposed) return;
+      timer = setTimeout(() => {
+        void poll().finally(schedule);
+      }, hasRunningPanels || remoteRunning ? 1000 : 10_000);
+    };
+    void poll().finally(schedule);
     return () => {
       disposed = true;
-      clearInterval(timer);
+      if (timer) clearTimeout(timer);
     };
-  }, []);
+  }, [hasRunningPanels]);
 }

application/state/usePluginAIContextHost.ts

@@ -3,8 +3,7 @@ import type { TerminalSession, Workspace } from '../../domain/models';
 import { getNotesSnapshot } from './notesStore';
 import { useActiveTabId } from './activeTabStore';
 import { getAppAppLockRuntime } from './appRuntimeBridge';
-import { createTrustedPluginAIHostRuntime } from '../../infrastructure/ai/plugin/trustedHostRuntime';
-import { getConfiguredPluginModel, prepareConfiguredPluginModel } from '../../infrastructure/ai/plugin/configuredModel';
+import type { createTrustedPluginAIHostRuntime } from '../../infrastructure/ai/plugin/trustedHostRuntime';
 import { buildSelectedPluginSources } from '../../infrastructure/ai/plugin/selectedSources';
 import { netcattyBridge } from '../../infrastructure/services/netcattyBridge';
 
@@ -27,30 +26,47 @@ export function usePluginAIContextHost({ sessions, workspaces }: { sessions: Ter
     let mounted = true;
     let chooser: { runtimeId: string; cancel: () => void } | null = null;
     const requests = new Map<string, { runtimeId: string; controller: AbortController }>();
-    const runtime = createTrustedPluginAIHostRuntime({
-      getModel: getConfiguredPluginModel,
-      prepareModel: prepareConfiguredPluginModel,
-      isActive: () => mounted && document.visibilityState === 'visible' && getAppAppLockRuntime()?.locked === false,
-      chooseSelected: (signal, runtimeId) => new Promise((resolve, reject) => {
-        if (chooser) { reject(Error('A host selection is already pending')); return; }
-        const finish = (id: string | null) => {
-          if (chooser?.cancel !== cancel) return;
-          chooser = null; signal.removeEventListener('abort', cancel); setChoice(null);
-          if (id === null || signal.aborted) { reject(Error('Selection cancelled')); return; }
-          selectedNoteId = id || null;
-          resolve(buildSelectedPluginSources(() => ({ ...latest.current,
-            note: getNotesSnapshot().notes.find((note) => note.id === selectedNoteId) ?? null })));
-        };
-        const cancel = () => finish(null);
-        chooser = { runtimeId, cancel };
-        signal.addEventListener('abort', cancel, { once: true });
-        setNoteId('');
-        // This inventory stays inside trusted host UI. The plugin receives
-        // summaries only for the Note chosen here and current selected scopes.
-        setNoteChoices(getNotesSnapshot().notes.map((note) => ({ id: note.id, title: note.title })));
-        setChoice({ confirm: (id) => finish(id), cancel });
-        if (signal.aborted) cancel();
-      }),
+    // The runtime pulls in the AI SDK providers (~1 MB with the Catty
+    // harness). This host is mounted for every main window, so create it on
+    // the first plugin AI request instead of at startup.
+    type HostRuntime = ReturnType<typeof createTrustedPluginAIHostRuntime>;
+    let runtime: HostRuntime | null = null;
+    let runtimeLoading: Promise<HostRuntime> | null = null;
+    const withLoadedRuntime = (apply: (loaded: HostRuntime) => void) => {
+      if (runtime) apply(runtime);
+      else void runtimeLoading?.then(apply, () => {});
+    };
+    const ensureRuntime = () => runtimeLoading ??= Promise.all([
+      import('../../infrastructure/ai/plugin/trustedHostRuntime'),
+      import('../../infrastructure/ai/plugin/configuredModel'),
+    ]).then(([{ createTrustedPluginAIHostRuntime: createRuntime }, { getConfiguredPluginModel, prepareConfiguredPluginModel }]) => {
+      runtime = createRuntime({
+        getModel: getConfiguredPluginModel,
+        prepareModel: prepareConfiguredPluginModel,
+        isActive: () => mounted && document.visibilityState === 'visible' && getAppAppLockRuntime()?.locked === false,
+        chooseSelected: (signal, runtimeId) => new Promise((resolve, reject) => {
+          if (chooser) { reject(Error('A host selection is already pending')); return; }
+          const finish = (id: string | null) => {
+            if (chooser?.cancel !== cancel) return;
+            chooser = null; signal.removeEventListener('abort', cancel); setChoice(null);
+            if (id === null || signal.aborted) { reject(Error('Selection cancelled')); return; }
+            selectedNoteId = id || null;
+            resolve(buildSelectedPluginSources(() => ({ ...latest.current,
+              note: getNotesSnapshot().notes.find((note) => note.id === selectedNoteId) ?? null })));
+          };
+          const cancel = () => finish(null);
+          chooser = { runtimeId, cancel };
+          signal.addEventListener('abort', cancel, { once: true });
+          setNoteId('');
+          // This inventory stays inside trusted host UI. The plugin receives
+          // summaries only for the Note chosen here and current selected scopes.
+          setNoteChoices(getNotesSnapshot().notes.map((note) => ({ id: note.id, title: note.title })));
+          setChoice({ confirm: (id) => finish(id), cancel });
+          if (signal.aborted) cancel();
+        }),
+      });
+      if (!mounted) runtime.shutdown();
+      return runtime;
     });
     const unsubscribe = bridge.onPluginAIHostRequest((request) => {
       if (request.kind === 'request.cancel') {
@@ -60,24 +76,28 @@ export function usePluginAIContextHost({ sessions, workspaces }: { sessions: Ter
       if (request.kind === 'runtime.release') {
         for (const pending of requests.values()) if (pending.runtimeId === request.runtimeId) pending.controller.abort();
         if (chooser?.runtimeId === request.runtimeId) chooser.cancel();
-        runtime.releaseRuntime(request.runtimeId);
+        withLoadedRuntime((loaded) => loaded.releaseRuntime(request.runtimeId));
         return;
       }
       if (requests.has(request.requestId) || requests.size >= 64) return;
       const controller = new AbortController();
       requests.set(request.requestId, { runtimeId: request.runtimeId, controller });
-      void runtime.handle(request.kind, request.payload, request.runtimeId, controller.signal).then(
+      void ensureRuntime().then((loaded) => {
+        // Loading is async: re-check that the host and request are still live.
+        if (!mounted || controller.signal.aborted) throw new Error('Plugin AI request is no longer active');
+        return loaded.handle(request.kind, request.payload, request.runtimeId, controller.signal);
+      }).then(
         (result) => bridge.respondPluginAIHost({ requestId: request.requestId, actionToken: request.actionToken, result }),
         () => bridge.respondPluginAIHost({ requestId: request.requestId, actionToken: request.actionToken, error: true }),
       ).catch(() => {}).finally(() => requests.delete(request.requestId));
     });
-    const pageHide = () => { runtime.shutdown(); for (const pending of requests.values()) pending.controller.abort(); };
+    const pageHide = () => { withLoadedRuntime((loaded) => loaded.shutdown()); for (const pending of requests.values()) pending.controller.abort(); };
     window.addEventListener('pagehide', pageHide);
     void bridge.setPluginAIHostReady(true).catch(() => {});
     return () => {
       mounted = false; chooser?.cancel(); unsubscribe(); window.removeEventListener('pagehide', pageHide);
       for (const pending of requests.values()) pending.controller.abort();
-      requests.clear(); runtime.shutdown();
+      requests.clear(); withLoadedRuntime((loaded) => loaded.shutdown());
       void bridge.setPluginAIHostReady(false).catch(() => {});
     };
   }, []);

application/state/usePluginAgentHost.ts

@@ -1,7 +1,7 @@
 import { useEffect, useRef, useState } from 'react';
 import type { TerminalSession } from '../../domain/models';
 import type { PluginAgentHostTerminal } from '@netcatty/plugin-contract';
-import { createTrustedPluginAgentRuntime } from '../../infrastructure/ai/pluginAgent/trustedAgentRuntime';
+import type { createTrustedPluginAgentRuntime } from '../../infrastructure/ai/pluginAgent/trustedAgentRuntime';
 import { netcattyBridge } from '../../infrastructure/services/netcattyBridge';
 import { getAppAppLockRuntime } from './appRuntimeBridge';
 import { LOCAL_STORAGE_ADAPTER_CHANGED_EVENT } from '../../infrastructure/persistence/localStorageAdapter';
@@ -22,58 +22,78 @@ export function usePluginAgentHost(sessions: TerminalSession[]) {
     let mounted = true;
     let chooser: { runtimeId: string; cancel: () => void } | null = null;
     const requests = new Map<string, { runtimeId: string; controller: AbortController }>();
-    const runtime = createTrustedPluginAgentRuntime({
-      isActive: () => mounted && document.visibilityState === 'visible' && getAppAppLockRuntime()?.locked === false,
-      chooseTargets: (signal, runtimeId) => new Promise((resolve, reject) => {
-        if (chooser) { reject(Error('A target selection is already pending')); return; }
-        const items = latest.current.filter((item) => item.status === 'connected').map((item) => ({
-          sessionId: item.id, hostId: item.hostId, hostname: (item.hostname || '').slice(0, 253),
-          label: (item.customName || item.hostLabel || item.id).slice(0, 160),
-          ...(item.protocol ? { protocol: item.protocol } : {}), ...(item.username ? { username: item.username.slice(0, 160) } : {}), connected: true,
-        }));
-        const finish = (ids: string[] | null) => {
-          if (chooser?.cancel !== cancel) return;
-          chooser = null; signal.removeEventListener('abort', cancel); setChoice(null);
-          if (ids === null || signal.aborted || ids.length > 32 || new Set(ids).size !== ids.length) { reject(Error('Target selection cancelled')); return; }
-          const selected = ids.map((id) => items.find((item) => item.sessionId === id));
-          if (selected.some((item) => !item || !latest.current.some((session) => session.id === item.sessionId && session.status === 'connected'))) {
-            reject(Error('Selected terminal is no longer connected')); return;
-          }
-          resolve(selected as PluginAgentHostTerminal[]);
-        };
-        const cancel = () => finish(null);
-        chooser = { runtimeId, cancel }; signal.addEventListener('abort', cancel, { once: true });
-        setChoice({ items, confirm: finish, cancel });
-        if (signal.aborted) cancel();
-      }),
-    });
+    // The agent runtime pulls in the whole Catty harness and AI SDK. This host
+    // is mounted for every main window, so create it on the first plugin agent
+    // request instead of at startup; until then there is nothing to cancel,
+    // release or invalidate.
+    type AgentRuntime = ReturnType<typeof createTrustedPluginAgentRuntime>;
+    let runtime: AgentRuntime | null = null;
+    let runtimeLoading: Promise<AgentRuntime> | null = null;
+    const withLoadedRuntime = (apply: (loaded: AgentRuntime) => void) => {
+      if (runtime) apply(runtime);
+      else void runtimeLoading?.then(apply, () => {});
+    };
+    const ensureRuntime = () => runtimeLoading ??= import('../../infrastructure/ai/pluginAgent/trustedAgentRuntime')
+      .then(({ createTrustedPluginAgentRuntime: createRuntime }) => {
+        runtime = createRuntime({
+          isActive: () => mounted && document.visibilityState === 'visible' && getAppAppLockRuntime()?.locked === false,
+          chooseTargets: (signal, runtimeId) => new Promise((resolve, reject) => {
+            if (chooser) { reject(Error('A target selection is already pending')); return; }
+            const items = latest.current.filter((item) => item.status === 'connected').map((item) => ({
+              sessionId: item.id, hostId: item.hostId, hostname: (item.hostname || '').slice(0, 253),
+              label: (item.customName || item.hostLabel || item.id).slice(0, 160),
+              ...(item.protocol ? { protocol: item.protocol } : {}), ...(item.username ? { username: item.username.slice(0, 160) } : {}), connected: true,
+            }));
+            const finish = (ids: string[] | null) => {
+              if (chooser?.cancel !== cancel) return;
+              chooser = null; signal.removeEventListener('abort', cancel); setChoice(null);
+              if (ids === null || signal.aborted || ids.length > 32 || new Set(ids).size !== ids.length) { reject(Error('Target selection cancelled')); return; }
+              const selected = ids.map((id) => items.find((item) => item.sessionId === id));
+              if (selected.some((item) => !item || !latest.current.some((session) => session.id === item.sessionId && session.status === 'connected'))) {
+                reject(Error('Selected terminal is no longer connected')); return;
+              }
+              resolve(selected as PluginAgentHostTerminal[]);
+            };
+            const cancel = () => finish(null);
+            chooser = { runtimeId, cancel }; signal.addEventListener('abort', cancel, { once: true });
+            setChoice({ items, confirm: finish, cancel });
+            if (signal.aborted) cancel();
+          }),
+        });
+        if (!mounted) runtime.shutdown();
+        return runtime;
+      });
     const unsubscribe = bridge.subscribe((request) => {
       if (request.kind === 'request.cancel') {
         const pending = requests.get(request.payload.requestId);
         if (pending?.runtimeId === request.runtimeId) pending.controller.abort();
-        runtime.cancelRequest(request.payload.requestId, request.runtimeId); return;
+        withLoadedRuntime((loaded) => loaded.cancelRequest(request.payload.requestId, request.runtimeId)); return;
       }
       if (request.kind === 'runtime.release') {
         for (const item of requests.values()) if (item.runtimeId === request.runtimeId) item.controller.abort();
         if (chooser?.runtimeId === request.runtimeId) chooser.cancel();
-        runtime.releaseRuntime(request.runtimeId); return;
+        withLoadedRuntime((loaded) => loaded.releaseRuntime(request.runtimeId)); return;
       }
-      if (request.kind === 'agent.close') { runtime.releaseChat(request.payload.chatSessionId, request.runtimeId); return; }
+      if (request.kind === 'agent.close') { withLoadedRuntime((loaded) => loaded.releaseChat(request.payload.chatSessionId, request.runtimeId)); return; }
       if (requests.has(request.requestId) || requests.size >= 64) return;
       const controller = new AbortController(); requests.set(request.requestId, { runtimeId: request.runtimeId, controller });
-      void runtime.handle(request, controller.signal).then(
+      void ensureRuntime().then((loaded) => {
+        // Loading is async: re-check that the host and request are still live.
+        if (!mounted || controller.signal.aborted) throw new Error('Plugin agent request is no longer active');
+        return loaded.handle(request, controller.signal);
+      }).then(
         (result) => bridge.respond({ requestId: request.requestId, actionToken: request.actionToken, result }).catch(() =>
           bridge.respond({ requestId: request.requestId, actionToken: request.actionToken, error: true })),
         () => bridge.respond({ requestId: request.requestId, actionToken: request.actionToken, error: true }),
       ).catch(() => {}).finally(() => requests.delete(request.requestId));
     });
-    const pageHide = () => { runtime.shutdown(); for (const item of requests.values()) item.controller.abort(); };
+    const pageHide = () => { withLoadedRuntime((loaded) => loaded.shutdown()); for (const item of requests.values()) item.controller.abort(); };
     const configurationKeys = new Set([STORAGE_KEY_AI_PROVIDERS, STORAGE_KEY_AI_ACTIVE_PROVIDER, STORAGE_KEY_AI_ACTIVE_MODEL,
       STORAGE_KEY_AI_AGENT_MODEL_MAP, STORAGE_KEY_AI_AGENT_PROVIDER_MAP, STORAGE_KEY_AI_EXTERNAL_AGENTS]);
     const configurationChanged = (event: Event) => {
       const key = event.type === 'storage' ? (event as StorageEvent).key : (event as CustomEvent<{ key: string }>).detail?.key;
       if (key === null || (key && configurationKeys.has(key))) {
-        runtime.invalidateConfiguration();
+        withLoadedRuntime((loaded) => loaded.invalidateConfiguration());
         // Invalidate main-owned backend leases too, even with no event read in
         // flight. Re-advertising availability does not renew existing handles.
         void bridge.ready(false).then(() => { if (mounted) return bridge.ready(true); }).catch(() => {});
@@ -85,7 +105,7 @@ export function usePluginAgentHost(sessions: TerminalSession[]) {
     return () => {
       mounted = false; chooser?.cancel(); unsubscribe(); window.removeEventListener('pagehide', pageHide);
       window.removeEventListener('storage', configurationChanged); window.removeEventListener(LOCAL_STORAGE_ADAPTER_CHANGED_EVENT, configurationChanged);
-      for (const item of requests.values()) item.controller.abort(); requests.clear(); runtime.shutdown();
+      for (const item of requests.values()) item.controller.abort(); requests.clear(); withLoadedRuntime((loaded) => loaded.shutdown());
       void bridge.ready(false).catch(() => {});
     };
   }, []);

application/state/usePluginCatalog.ts

@@ -10,6 +10,7 @@ export function usePluginCatalog(selectedId: string | null, sourceId = 'official
   const [listAttempt, setListAttempt] = useState(0);
   const [readmeState, setReadmeState] = useState<ReadmeState | null>(null);
   const [readmeAttempt, setReadmeAttempt] = useState(0);
+  const [imageState, setImageState] = useState<{ id: string; token?: string; sourceId: string; images: Record<string, string> } | null>(null);
   const [installError, setInstallError] = useState<{ id: string; message: string } | null>(null);
   const [busy, setBusy] = useState(false);
   const [sourceBinding, setSourceBinding] = useState<NetcattyPluginSource | null>(null);
@@ -51,9 +52,19 @@ export function usePluginCatalog(selectedId: string | null, sourceId = 'official
     })();
     return () => { active = false; };
   }, [selectedId, selectionToken, readmeAttempt, sourceId]);
+  useEffect(() => {
+    let active = true;
+    if (selectedId && selectionToken) {
+      void netcattyBridge.get()?.getPluginCatalogReadmeImages?.(selectedId, selectionToken, sourceId)
+        .then((images) => { if (active) setImageState({ id: selectedId, token: selectionToken, sourceId, images }); })
+        .catch(() => { if (active) setImageState(null); });
+    }
+    return () => { active = false; };
+  }, [selectedId, selectionToken, sourceId, readmeAttempt]);
   const currentReadme = readmeState?.id === selectedId && readmeState.token === selectionToken && readmeState.attempt === readmeAttempt ? readmeState : null;
   return {
     entries, listStatus, listError, source, sourceBinding,
+    readmeImages: imageState?.id === selectedId && imageState.token === selectionToken && imageState.sourceId === sourceId ? imageState.images : {},
     readme: currentReadme?.status === 'ready' ? currentReadme.text : null,
     readmeStatus: currentReadme?.status ?? (selectedId ? 'loading' : 'idle'),
     readmeError: currentReadme?.error ?? null,

application/state/usePluginContributions.ts

@@ -86,14 +86,8 @@ export interface UsePluginContributionsResult {
   updateSetting(pluginId: string, settingId: string, value: unknown, scopeId?: string): Promise<{ restartRequired: boolean }>;
   resetSetting(pluginId: string, settingId: string, scopeId?: string): Promise<{ restartRequired: boolean }>;
   selectSettingPath(kind: 'file' | 'directory', title: string, defaultPath?: string): Promise<string | null>;
-  openView(payload: NetcattyPluginViewOpenRequest): Promise<{ instanceId: string }>;
-  closeView(instanceId: string): Promise<void>;
-  focusView(instanceId: string): Promise<void>;
-  setViewBounds(instanceId: string, bounds: { x: number; y: number; width: number; height: number }): Promise<void>;
-  setViewVisibility(instanceId: string, visible: boolean): Promise<void>;
   setEnvironment(environment: NetcattyPluginEnvironment): Promise<void>;
   onViewClosed(callback: (event: NetcattyPluginViewClosedEvent) => void): () => void;
-  onViewFocused(callback: (event: import('@netcatty/plugin-contract').PluginViewFocusEvent) => void): () => void;
 }
 
 export function usePluginContributions(
@@ -189,32 +183,6 @@ export function usePluginContributions(
     return picker(title, defaultPath);
   }, [bridge]);
 
-  const openView = useCallback(async (payload: NetcattyPluginViewOpenRequest) => {
-    if (!bridge?.openPluginView) throw new Error('Plugin views are unavailable');
-    return bridge.openPluginView(payload);
-  }, [bridge]);
-
-  const closeView = useCallback(async (instanceId: string) => {
-    if (!bridge?.closePluginView) return;
-    await bridge.closePluginView(instanceId);
-  }, [bridge]);
-  const focusView = useCallback(async (instanceId: string) => {
-    await bridge?.focusPluginView?.({ instanceId });
-  }, [bridge]);
-
-  const setViewBounds = useCallback(async (
-    instanceId: string,
-    bounds: { x: number; y: number; width: number; height: number },
-  ) => {
-    if (!bridge?.setPluginViewBounds) return;
-    await bridge.setPluginViewBounds(instanceId, bounds);
-  }, [bridge]);
-
-  const setViewVisibility = useCallback(async (instanceId: string, visible: boolean) => {
-    if (!bridge?.setPluginViewVisibility) return;
-    await bridge.setPluginViewVisibility(instanceId, visible);
-  }, [bridge]);
-
   const setEnvironment = useCallback(async (environment: NetcattyPluginEnvironment) => {
     if (!bridge?.setPluginEnvironment) return;
     await bridge.setPluginEnvironment(environment);
@@ -223,10 +191,6 @@ export function usePluginContributions(
   const onViewClosed = useCallback((callback: (event: NetcattyPluginViewClosedEvent) => void) => (
     bridge?.onPluginViewClosed?.(callback) ?? (() => {})
   ), [bridge]);
-  const onViewFocused = useCallback((callback: (event: import('@netcatty/plugin-contract').PluginViewFocusEvent) => void) => (
-    bridge?.onPluginViewFocused?.(callback) ?? (() => {})
-  ), [bridge]);
-
   const currentLoadState = resolvePluginContributionLoadState({
     currentQueryKey: queryKey,
     loadedQueryKey: loadedSnapshot.queryKey,
@@ -245,13 +209,7 @@ export function usePluginContributions(
     updateSetting,
     resetSetting,
     selectSettingPath,
-    openView,
-    closeView,
-    focusView,
-    setViewBounds,
-    setViewVisibility,
     setEnvironment,
     onViewClosed,
-    onViewFocused,
   };
 }

application/state/usePluginManager.ts

@@ -38,18 +38,20 @@ export function usePluginManager() {
     const refreshGeneration = generation;
     return () => { refreshGeneration.current++; unsubscribe?.(); window.removeEventListener('netcatty:plugin-packages-changed', update); };
   }, [refresh]);
-  const run = useCallback(async (action: (bridge: NetcattyBridge) => Promise<unknown>) => {
+  const run = useCallback(async (action: (bridge: NetcattyBridge) => Promise<unknown>, throwOnError = false) => {
     if (mutation.current) return;
     mutation.current = true;
     setBusy(true);
     setError(null);
+    let failure: Error | null = null;
     try { await action(netcattyBridge.require()); }
-    catch (cause) { setError(cause instanceof Error ? cause.message : String(cause)); }
+    catch (cause) { failure = cause instanceof Error ? cause : new Error(String(cause)); setError(failure.message); }
     finally {
-      try { await refresh(); } catch (cause) { setError(String(cause)); }
+      try { await refresh(); } catch (cause) { failure ??= cause instanceof Error ? cause : new Error(String(cause)); setError(failure.message); }
       mutation.current = false;
       setBusy(false);
     }
+    if (throwOnError && failure) throw failure;
   }, [refresh]);
   return {
     plugins, available, statusKnown, busy, error, credentialStorageAvailable, refresh,
@@ -70,6 +72,6 @@ export function usePluginManager() {
         if (!bridge.resetPluginSource) throw new Error('Private source reset unavailable');
         await bridge.resetPluginSource(id, source.id);
       }
-    }),
+    }, true),
   };
 }

application/state/usePluginSettingsModel.ts

@@ -0,0 +1,22 @@
+import { useEffect, useMemo, useState } from 'react';
+import { useI18n } from '../i18n/I18nProvider';
+import { usePluginContributions } from './usePluginContributions';
+import { resolvePluginSettingScopeSelection, usePluginSettingScopeCatalog } from './usePluginSettingScopeCatalog';
+
+export function usePluginSettingsModel(pluginId: string) {
+  const { locale } = useI18n();
+  const catalog = usePluginSettingScopeCatalog();
+  const [scopeIds, setScopeIds] = useState<Partial<Record<NetcattyPluginSettingScopeKind, string>>>({});
+  useEffect(() => {
+    setScopeIds(current => resolvePluginSettingScopeSelection(catalog, current));
+  }, [catalog]);
+  const query = useMemo<NetcattyPluginContributionQuery>(() => ({
+    locale, context: { 'netcatty.surface': 'settings' }, scopeIds,
+  }), [locale, scopeIds]);
+  const contributions = usePluginContributions(query);
+  const plugin = contributions.snapshot.plugins.find(item => item.id === pluginId);
+  const settings = plugin?.settings.filter(setting => setting.visible) ?? [];
+  const contextualScopes = [...new Set(settings.map(setting => setting.scope)
+    .filter((scope): scope is NetcattyPluginSettingScopeKind => scope !== 'application'))];
+  return { ...contributions, plugin, settings, catalog, scopeIds, setScopeIds, contextualScopes };
+}

application/state/usePluginViewLifecycle.ts

@@ -14,19 +14,12 @@ import {
   usePluginViewTabs,
 } from './pluginViewTabStore';
 import {
-  PluginViewLifecycleController,
   reconcilePluginViewTabCatalog,
   resolvePluginViewSnapshotSelection,
-  type HostedPluginViewState,
   type PluginViewSnapshotSelection,
 } from './pluginViewLifecycle';
-import {
-  canRetainPluginViewInScope,
-  resolvePluginRetainedViewKey,
-  resolvePluginViewWindowScope,
-} from './pluginViewScopes';
+import { pluginViewSessions } from './pluginViewSession';
 import { usePluginContributions } from './usePluginContributions';
-import { observePluginHostSecurityVisibility } from './pluginHostSecurityVisibility';
 
 export const OPEN_PLUGIN_VIEW_EVENT = 'netcatty:open-plugin-view';
 
@@ -70,17 +63,8 @@ export function usePluginViewLifecycle({
   const {
     snapshot,
     executeCommand,
-    openView,
-    closeView,
-    setViewBounds,
-    setViewVisibility,
     setEnvironment,
-    onViewClosed,
   } = contributions;
-  const [instance, setInstance] = useState<HostedPluginViewState | null>(null);
-  const lifecycleRef = useRef(new PluginViewLifecycleController<HostedPluginViewState>());
-  const closeViewRef = useRef(closeView);
-  const mountRef = useRef<HTMLDivElement>(null);
   const resolvedActiveView = useMemo(() => viewContributions.snapshot.plugins
     .flatMap((plugin) => plugin.views.map((view) => ({ plugin, view })))
     .find(({ view }) => view.id === effectiveRequested?.viewId && view.visible && !['vault-page', 'terminal-sidebar'].includes(view.location)) ?? null,
@@ -93,16 +77,6 @@ export function usePluginViewLifecycle({
     requestedViewId: effectiveRequested?.viewId,
     contextKey: viewQueryContextKey,
   });
-  const activeViewId = activeView?.view.id;
-  const viewScopeId = typeof window === 'undefined'
-    ? 'window:server'
-    : resolvePluginViewWindowScope(window.location);
-  const retainedViewKey = activeViewId
-    ? resolvePluginRetainedViewKey(activeViewId, viewScopeId)
-    : null;
-
-  useEffect(() => { closeViewRef.current = closeView; }, [closeView]);
-
   useEffect(() => {
     if (viewContributions.loading) return;
     stableActiveViewRef.current = resolvedActiveView && effectiveRequested?.viewId
@@ -114,26 +88,6 @@ export function usePluginViewLifecycle({
       : null;
   }, [effectiveRequested?.viewId, resolvedActiveView, viewContributions.loading, viewQueryContextKey]);
 
-  useEffect(() => onViewClosed((event) => {
-    const next = lifecycleRef.current.handleHostClose(event.instanceId);
-    if (next.matchedCurrent) {
-      setInstance(null);
-      setRequested(null);
-    }
-    if (next.closedTabId) pluginViewTabStore.close(next.closedTabId);
-  }), [onViewClosed]);
-
-  useEffect(() => pluginViewTabStore.onDidClose(({ tab }) => {
-    const next = lifecycleRef.current.handleTabClose(tab.id);
-    if (next.matchedCurrent) {
-      setInstance(null);
-      setRequested(null);
-    }
-    for (const instanceId of next.instanceIds) {
-      void closeViewRef.current(instanceId).catch(() => {});
-    }
-  }), []);
-
   useEffect(() => {
     const bindings = snapshot.plugins.flatMap((plugin) => plugin.keybindings)
       .filter((binding) => binding.enabled)
@@ -182,164 +136,16 @@ export function usePluginViewLifecycle({
     setRequested(null);
   }, [activeView, requested]);
 
-  const hideOrClose = useCallback(async (current: HostedPluginViewState) => {
-    if (!current.retainContextWhenHidden) {
-      await closeView(current.id);
-      return;
-    }
-    const key = resolvePluginRetainedViewKey(current.viewId, current.scopeId);
-    lifecycleRef.current.retain(key, current);
-    try {
-      await setViewVisibility(current.id, false);
-    } catch {
-      lifecycleRef.current.removeRetained(key);
-      await closeView(current.id);
-    }
-  }, [closeView, setViewVisibility]);
+  useEffect(() => {
+    const stop = pluginViewTabStore.onDidClose(({ tab }) => pluginViewSessions.closeView(tab.viewId));
+    return () => { stop(); };
+  }, []);
 
   const close = useCallback(async () => {
-    lifecycleRef.current.markViewClosed(retainedViewKey);
-    const current = lifecycleRef.current.takeCurrent();
-    setInstance(null);
     setRequested(null);
-    if (current) await closeView(current.id);
-  }, [closeView, retainedViewKey]);
-
-  useEffect(() => {
-    const removed = lifecycleRef.current.removeRetainedWhere(
-      (retained) => !canRetainPluginViewInScope(retained.scopeId, viewScopeId),
-    );
-    for (const retained of removed) void closeView(retained.id).catch(() => {});
-  }, [closeView, viewScopeId]);
-
-  useEffect(() => {
-    if (!instance) return;
-    if (effectiveRequested?.viewId === instance.viewId
-      && activeViewId === instance.viewId
-      && instance.scopeId === viewScopeId) return;
-    lifecycleRef.current.takeCurrent();
-    setInstance(null);
-    if (canRetainPluginViewInScope(instance.scopeId, viewScopeId)) {
-      void hideOrClose(instance);
-    } else {
-      void closeView(instance.id).catch(() => {});
-    }
-  }, [activeViewId, closeView, effectiveRequested?.viewId, hideOrClose, instance, viewScopeId]);
-
-  useEffect(() => {
-    if (!activeViewId || !retainedViewKey || !mountRef.current || instance) return;
-    let cancelled = false;
-    const openingTabId = activePluginTab?.id;
-    const openingToken = lifecycleRef.current.beginOpen({
-      viewKey: retainedViewKey,
-      tabId: openingTabId,
-      label: activePluginTab?.id ?? activeViewId,
-    });
-    const bounds = mountRef.current.getBoundingClientRect();
-    const nextBounds = {
-      x: Math.round(bounds.x),
-      y: Math.round(bounds.y),
-      width: Math.max(1, Math.round(bounds.width)),
-      height: Math.max(1, Math.round(bounds.height)),
-    };
-    void (async () => {
-      let opened = lifecycleRef.current.takeRetained(retainedViewKey);
-      if (opened) {
-        try {
-          await setViewBounds(opened.id, nextBounds);
-          await setViewVisibility(opened.id, true);
-        } catch {
-          try { await closeView(opened.id); } catch { /* best-effort cleanup after restore failure */ }
-          opened = null;
-        }
-      }
-      if (!opened) {
-        const result = await openView({
-          viewId: activeViewId,
-          scopeId: viewScopeId,
-          bounds: nextBounds,
-          context: effectiveRequested?.context,
-        });
-        opened = {
-          id: result.instanceId,
-          viewId: activeViewId,
-          scopeId: viewScopeId,
-          retainContextWhenHidden: activeView.view.retainContextWhenHidden === true,
-          ...(activePluginTab ? { tabId: activePluginTab.id } : {}),
-        };
-      }
-      if (lifecycleRef.current.consumeHostClose(opened.id)) {
-        throw new Error('Plugin view closed while its open response was in flight');
-      }
-      if (lifecycleRef.current.shouldCloseOpen(openingToken)) {
-        await closeView(opened.id);
-        return;
-      }
-      if (cancelled) {
-        await hideOrClose(opened);
-        return;
-      }
-      lifecycleRef.current.setCurrent(opened);
-      setInstance(opened);
-    })().catch(() => {
-      if (cancelled) return;
-      if (activePluginTab) pluginViewTabStore.close(activePluginTab.id);
-      else setRequested(null);
-    }).finally(() => {
-      lifecycleRef.current.finishOpen({
-        token: openingToken,
-        viewKey: retainedViewKey,
-        tabId: openingTabId,
-      });
-    });
-    return () => { cancelled = true; };
-  }, [
-    activePluginTab,
-    activeView?.view.retainContextWhenHidden,
-    activeViewId,
-    closeView,
-    effectiveRequested?.context,
-    hideOrClose,
-    instance,
-    openView,
-    retainedViewKey,
-    setViewBounds,
-    setViewVisibility,
-    viewScopeId,
-  ]);
-
-  useEffect(() => {
-    if (!instance || !mountRef.current) return;
-    let disposed = false;
-    const stop = observePluginHostSecurityVisibility(mountRef.current, (visible) => {
-      void setViewVisibility(instance.id, visible).catch(() => {
-        if (!disposed) void closeView(instance.id).catch(() => {});
-      });
-    });
-    return () => { disposed = true; stop(); };
-  }, [closeView, instance, setViewVisibility]);
-
-  useEffect(() => {
-    if (!instance || !mountRef.current) return;
-    const update = () => {
-      const bounds = mountRef.current?.getBoundingClientRect();
-      if (!bounds) return;
-      void setViewBounds(instance.id, {
-        x: Math.round(bounds.x),
-        y: Math.round(bounds.y),
-        width: Math.max(1, Math.round(bounds.width)),
-        height: Math.max(1, Math.round(bounds.height)),
-      });
-    };
-    const observer = new ResizeObserver(update);
-    observer.observe(mountRef.current);
-    window.addEventListener('resize', update);
-    update();
-    return () => {
-      observer.disconnect();
-      window.removeEventListener('resize', update);
-    };
-  }, [instance, setViewBounds]);
+    if (activeView) pluginViewSessions.closeView(activeView.view.id);
+    if (activePluginTab) pluginViewTabStore.close(activePluginTab.id);
+  }, [activePluginTab, activeView]);
 
   useEffect(() => {
     if (!contributions.available) return;
@@ -376,16 +182,10 @@ export function usePluginViewLifecycle({
     };
   }, [contributions.available, locale, setEnvironment, suppliedThemeTokens, theme]);
 
-  useEffect(() => () => {
-    const views = lifecycleRef.current.drain();
-    const ids = new Set(views.map((view) => view.id));
-    for (const id of ids) void closeViewRef.current(id);
-  }, []);
-
   return {
     activeView,
     close,
     effectiveRequested,
-    mountRef,
+    viewQueryContext,
   };
 }

application/state/useServerStats.ts

@@ -2,6 +2,8 @@ import { useCallback, useEffect, useRef, useState } from 'react';
 import { netcattyBridge } from '../../infrastructure/services/netcattyBridge';
 
 export interface DiskInfo {
+  diskReadSpeed?: number | null; // Mounted block-device I/O, bytes/sec
+  diskWriteSpeed?: number | null;
   capacityKey?: string;       // Filesystem or shared-pool identity for deduplication
   filesystemType?: string;    // Filesystem type reported by df (for network/FUSE filtering)
   mountPoint: string;

application/state/useSessionState.ts

@@ -21,9 +21,11 @@ getNextFocusSessionId,
 insertPaneIntoWorkspace,
 pruneWorkspaceNode,
 reorderWorkspaceFocusSessionOrder,
+setWorkspaceFocusedSessionId,
 SplitDirection,
 SplitHint,
 updateWorkspaceSplitSizes,
+  invertSplitPosition,
 } from '../../domain/workspace';
 import { clearSessionFontSizeOverride as clearSessionFontSizeOverrideFields } from '../../domain/terminalAppearance';
 import {
@@ -248,6 +250,8 @@ export const useSessionState = ({
   const [globalComposeSendToAll, setGlobalComposeSendToAll] = useState<boolean>(false);
   // Log views: stores open log replay tabs
   const [logViews, setLogViews] = useState<LogView[]>([]);
+  const logViewsRef = useRef(logViews);
+  logViewsRef.current = logViews;
   const [restorePreviousSessionRevision, setRestorePreviousSessionRevision] = useState(0);
   const sessionsRef = useRef(sessions);
   const tabOrderRef = useRef(tabOrder);
@@ -795,12 +799,68 @@ export const useSessionState = ({
     return workspace.id;
   }, [setActiveTabId]);
 
+  const addSessionToWorkspace = useCallback((
+    workspaceId: string,
+    sessionId: string,
+    hint: SplitHint
+  ) => {
+    if (!hint) return;
+    
+	    setSessions(prevSessions => {
+      const session = prevSessions.find(s => s.id === sessionId);
+      if (!session || session.workspaceId) return prevSessions;
+      
+      setWorkspaces(prevWorkspaces => {
+        const targetWorkspace = prevWorkspaces.find(w => w.id === workspaceId);
+        if (!targetWorkspace) return prevWorkspaces;
+        
+        return insertWorkspacePaneIfMissing(prevWorkspaces, workspaceId, sessionId, hint);
+      });
+      
+      setActiveTabId(workspaceId);
+      return prevSessions.map(s => s.id === sessionId ? { ...s, workspaceId } : s);
+	    });
+	  }, [setActiveTabId]);
+
+  // Merge two tabs into one workspace. When one of them already belongs to a
+  // workspace, that workspace (and its id) is reused instead of dissolving
+  // and recreating: the id is what workspace-scoped AI chats bind to, so
+  // regenerating it used to strand every conversation anchored to it
+  // (issue #4015 R3). Only two genuinely standalone tabs create a new id.
   const createWorkspaceFromSessions = useCallback((
     baseSessionId: string,
     joiningSessionId: string,
     hint: SplitHint
   ) => {
     if (!hint || baseSessionId === joiningSessionId) return;
+    const baseSession = sessionsRef.current.find((s) => s.id === baseSessionId);
+    const joiningSession = sessionsRef.current.find((s) => s.id === joiningSessionId);
+    const anchorWorkspaceId = baseSession?.workspaceId ?? joiningSession?.workspaceId;
+    if (anchorWorkspaceId) {
+      const anchorSessionId = baseSession?.workspaceId ? baseSessionId : joiningSessionId;
+      const orphanSessionId = anchorSessionId === baseSessionId ? joiningSessionId : baseSessionId;
+      const orphanSession = sessionsRef.current.find((s) => s.id === orphanSessionId);
+      if (!orphanSession || orphanSession.workspaceId) return;
+      // Split next to the anchor's existing pane: the raw drop hint targets
+      // the orphan's pane, which is not part of this workspace tree yet.
+      // When the dragged (joining) pane already owns the workspace, the orphan
+      // is what gets inserted — invert the drop position so the previewed
+      // side still matches (hint describes where the dragged pane should sit).
+      const joinOwnsWorkspace = Boolean(joiningSession?.workspaceId) && !baseSession?.workspaceId;
+      const insertHint = {
+        ...hint,
+        targetSessionId: anchorSessionId,
+        position: joinOwnsWorkspace ? invertSplitPosition(hint.position) : hint.position,
+      };
+      addSessionToWorkspace(
+        anchorWorkspaceId,
+        orphanSessionId,
+        insertHint,
+      );
+      // The orphan's standalone tab slot is replaced by the workspace tab.
+      setTabOrder((prevTabOrder) => prevTabOrder.filter((id) => id !== orphanSessionId));
+      return;
+    }
     // Name the merged workspace after both tabs' connection labels (e.g.
     // "01/02") so the window title and the rename dialog show the merged
     // identity instead of the generic "Workspace". Falls back to the default
@@ -855,30 +915,7 @@ export const useSessionState = ({
         return s;
       });
     });
-  }, [setActiveTabId]);
-
-  const addSessionToWorkspace = useCallback((
-    workspaceId: string,
-    sessionId: string,
-    hint: SplitHint
-  ) => {
-    if (!hint) return;
-    
-	    setSessions(prevSessions => {
-      const session = prevSessions.find(s => s.id === sessionId);
-      if (!session || session.workspaceId) return prevSessions;
-      
-      setWorkspaces(prevWorkspaces => {
-        const targetWorkspace = prevWorkspaces.find(w => w.id === workspaceId);
-        if (!targetWorkspace) return prevWorkspaces;
-        
-        return insertWorkspacePaneIfMissing(prevWorkspaces, workspaceId, sessionId, hint);
-      });
-      
-      setActiveTabId(workspaceId);
-      return prevSessions.map(s => s.id === sessionId ? { ...s, workspaceId } : s);
-	    });
-	  }, [setActiveTabId]);
+  }, [addSessionToWorkspace, setActiveTabId]);
 
   // Add a host into an existing workspace by creating a new session for
   // that host and appending it as the last pane at the workspace root.
@@ -1063,10 +1100,10 @@ export const useSessionState = ({
 
   // Set the focused session in a workspace (for focus mode)
   const setWorkspaceFocusedSession = useCallback((workspaceId: string, sessionId: string) => {
-    setWorkspaces(prev => prev.map(ws => {
-      if (ws.id !== workspaceId) return ws;
-      return { ...ws, focusedSessionId: sessionId };
-    }));
+    // Pane click and focus both land here; an unchanged focus must keep the
+    // same array or every click re-renders the whole shell (and re-saves the
+    // session restore snapshot).
+    setWorkspaces(prev => setWorkspaceFocusedSessionId(prev, workspaceId, sessionId));
   }, []);
 
   const reorderWorkspaceSessions = useCallback((
@@ -1092,7 +1129,7 @@ export const useSessionState = ({
 
   // Move focus between panes in a workspace
   const moveFocusInWorkspace = useCallback((workspaceId: string, direction: FocusDirection): boolean => {
-    const workspace = workspaces.find(w => w.id === workspaceId);
+    const workspace = workspacesRef.current.find(w => w.id === workspaceId);
     if (!workspace) {
       return false;
     }
@@ -1113,13 +1150,10 @@ export const useSessionState = ({
     }
     
     // Update focused session
-    setWorkspaces(prev => prev.map(ws => {
-      if (ws.id !== workspaceId) return ws;
-      return { ...ws, focusedSessionId: nextSessionId };
-    }));
+    setWorkspaces(prev => setWorkspaceFocusedSessionId(prev, workspaceId, nextSessionId));
     
     return true;
-  }, [workspaces]);
+  }, []);
 
   // Run a snippet on multiple target hosts - creates a focus mode workspace
   const runSnippet = useCallback((snippet: Snippet, targetHosts: Host[], commandOverride?: string) => {
@@ -1162,6 +1196,10 @@ export const useSessionState = ({
 	  }, [setActiveTabId]);
 
   const orphanSessions = useMemo(() => sessions.filter(s => !s.workspaceId && !s.hiddenFromTabs), [sessions]);
+  // Read by action callbacks at call time so they keep a stable identity:
+  // orphanSessions changes with every session status update.
+  const orphanSessionsRef = useRef(orphanSessions);
+  orphanSessionsRef.current = orphanSessions;
   const canUseGlobalBroadcast = orphanSessions.length >= 2;
 
   // Losing the group must disarm broadcast before another tab can join it.
@@ -1196,6 +1234,13 @@ export const useSessionState = ({
   }) => {
     // Pre-allocate the new id outside the updater so StrictMode's
     // double-invocation of the functional updater doesn't mint two ids.
+    // Same snapshot the old closure captured (values at click time), read from
+    // refs so this action keeps a stable identity across session updates.
+    const tabIdsAtCall = [
+      ...orphanSessionsRef.current.map(s => s.id),
+      ...workspacesRef.current.map(w => w.id),
+      ...logViewsRef.current.map(lv => lv.id),
+    ];
     const newSessionId = crypto.randomUUID();
 
     setSessions(prevSessions => {
@@ -1216,17 +1261,13 @@ export const useSessionState = ({
       // StrictMode's double-invocation is harmless.
       setActiveTabId(newSessionId);
       setTabOrder(prevTabOrder => {
-        const allTabIds = [
-          ...orphanSessions.map(s => s.id),
-          ...workspaces.map(w => w.id),
-          ...logViews.map(lv => lv.id),
-        ];
+        const allTabIds = tabIdsAtCall;
         return insertCopiedTabOrderIdOnce(prevTabOrder, sessionId, newSessionId, allTabIds);
       });
 
       return [...prevSessions, newSession];
     });
-  }, [orphanSessions, workspaces, logViews, setActiveTabId]);
+  }, [setActiveTabId]);
 
   // Copy a whole workspace (split/focus tab): clone every pane's session and
   // reproduce the layout tree in a new tab.
@@ -1234,7 +1275,14 @@ export const useSessionState = ({
     localShellType?: TerminalSession['shellType'];
     perPaneCwd?: Record<string, string | undefined>;
   }) => {
-    const sourceWorkspace = workspaces.find(w => w.id === workspaceId);
+    // Same snapshot the old closure captured (values at click time), read from
+    // refs so this action keeps a stable identity across session updates.
+    const tabIdsAtCall = [
+      ...orphanSessionsRef.current.map(s => s.id),
+      ...workspacesRef.current.map(w => w.id),
+      ...logViewsRef.current.map(lv => lv.id),
+    ];
+    const sourceWorkspace = workspacesRef.current.find(w => w.id === workspaceId);
     if (!sourceWorkspace) return;
 
     // Pre-mint the new workspace id and the old->new session-id map OUTSIDE the
@@ -1272,17 +1320,13 @@ export const useSessionState = ({
       setWorkspaces(prev => addWorkspaceIfMissing(prev, built.newWorkspace));
       setActiveTabId(newWorkspaceId);
       setTabOrder(prevTabOrder => {
-        const allTabIds = [
-          ...orphanSessions.map(s => s.id),
-          ...workspaces.map(w => w.id),
-          ...logViews.map(lv => lv.id),
-        ];
+        const allTabIds = tabIdsAtCall;
         return insertCopiedTabOrderIdOnce(prevTabOrder, workspaceId, newWorkspaceId, allTabIds);
       });
 
       return [...prevSessions, ...built.newSessions];
     });
-  }, [workspaces, orphanSessions, logViews, setActiveTabId]);
+  }, [setActiveTabId]);
 
   const createSessionFromCloneSource = useCallback((sourceSession: TerminalSession, options?: {
     localShellType?: TerminalSession['shellType'];

application/state/useSessionStateWorkspaceIdReuse.test.ts

@@ -0,0 +1,146 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import React from "react";
+import { act, create, type ReactTestRenderer } from "react-test-renderer";
+
+import { collectSessionIds } from "../../domain/workspace.ts";
+import { useSessionState } from "./useSessionState.ts";
+
+type SessionState = ReturnType<typeof useSessionState>;
+
+test("merging a workspace tab with a standalone tab reuses the workspace id (issue #4015 R3)", async (t) => {
+  const previousWindow = Object.getOwnPropertyDescriptor(globalThis, "window");
+  const eventTarget = new EventTarget() as EventTarget & Record<string, unknown>;
+  Object.assign(eventTarget, {
+    setTimeout,
+    clearTimeout,
+  });
+  Object.defineProperty(globalThis, "window", {
+    configurable: true,
+    value: eventTarget,
+  });
+  t.after(() => {
+    if (previousWindow) Object.defineProperty(globalThis, "window", previousWindow);
+    else Reflect.deleteProperty(globalThis, "window");
+  });
+
+  const actEnvironment = globalThis as typeof globalThis & {
+    IS_REACT_ACT_ENVIRONMENT?: boolean;
+  };
+  const previousActEnvironment = actEnvironment.IS_REACT_ACT_ENVIRONMENT;
+  actEnvironment.IS_REACT_ACT_ENVIRONMENT = true;
+  t.after(() => {
+    actEnvironment.IS_REACT_ACT_ENVIRONMENT = previousActEnvironment;
+  });
+
+  let state: SessionState | null = null;
+  let renderer: ReactTestRenderer | null = null;
+  const current = (): SessionState => {
+    assert.ok(state);
+    return state;
+  };
+  function Probe() {
+    state = useSessionState({ persistSessionRestore: false });
+    return null;
+  }
+
+  await act(async () => {
+    renderer = create(React.createElement(Probe));
+  });
+
+  let baseId = "";
+  let memberId = "";
+  let standaloneId = "";
+  await act(async () => {
+    baseId = current().createLocalTerminal({ shellName: "01" });
+    memberId = current().createLocalTerminal({ shellName: "02" });
+    standaloneId = current().createLocalTerminal({ shellName: "03" });
+  });
+
+  await act(async () => {
+    current().createWorkspaceFromSessions(baseId, memberId, {
+      direction: "vertical",
+      position: "right",
+      targetSessionId: baseId,
+    });
+  });
+  const workspaceId = current().workspaces[0]?.id;
+  assert.ok(workspaceId);
+  assert.equal(current().sessions.find((s) => s.id === standaloneId)?.workspaceId ?? "", "");
+
+  // Dropping the standalone tab onto a member of the workspace must join the
+  // existing workspace — regenerating the id would strand AI chats bound to it.
+  await act(async () => {
+    current().createWorkspaceFromSessions(standaloneId, memberId, {
+      direction: "vertical",
+      position: "right",
+      targetSessionId: standaloneId,
+    });
+  });
+
+  assert.equal(current().workspaces.length, 1);
+  assert.equal(current().workspaces[0]?.id, workspaceId);
+  assert.equal(
+    current().sessions.find((s) => s.id === standaloneId)?.workspaceId,
+    workspaceId,
+  );
+  const memberIds = collectSessionIds(current().workspaces[0]!.root);
+  assert.ok(memberIds.includes(standaloneId));
+  assert.ok(memberIds.includes(memberId));
+  // The standalone tab slot is replaced by the workspace tab.
+  assert.ok(!current().orderedTabs.includes(standaloneId));
+
+
+  // Dropping a workspace member onto a standalone tab must insert the
+  // standalone on the opposite side of the drop hint (hint describes where
+  // the dragged member should appear relative to the standalone).
+  let orientationStandaloneId = "";
+  await act(async () => {
+    orientationStandaloneId = current().createLocalTerminal({ shellName: "orient-standalone" });
+  });
+  // memberId is already in workspaceId; drop member onto the new standalone with position "right"
+  // (preview: member to the right of standalone ⇒ standalone should end up LEFT of member).
+  await act(async () => {
+    current().createWorkspaceFromSessions(orientationStandaloneId, memberId, {
+      direction: "vertical",
+      position: "right",
+      targetSessionId: orientationStandaloneId,
+    });
+  });
+  {
+    const root = current().workspaces.find((ws) => ws.id === workspaceId)?.root;
+    assert.ok(root);
+    const ordered = collectSessionIds(root!);
+    const standaloneIdx = ordered.indexOf(orientationStandaloneId);
+    const memberIdx = ordered.indexOf(memberId);
+    assert.ok(standaloneIdx >= 0 && memberIdx >= 0);
+    assert.ok(
+      standaloneIdx < memberIdx,
+      `expected standalone left of member after inverted right-drop, got order ${ordered.join(",")}`,
+    );
+  }
+
+  // Two genuinely standalone tabs still create a fresh workspace.
+  let firstStandaloneId = "";
+  let secondStandaloneId = "";
+  await act(async () => {
+    firstStandaloneId = current().createLocalTerminal({ shellName: "04" });
+    secondStandaloneId = current().createLocalTerminal({ shellName: "05" });
+  });
+  await act(async () => {
+    current().createWorkspaceFromSessions(firstStandaloneId, secondStandaloneId, {
+      direction: "vertical",
+      position: "right",
+      targetSessionId: firstStandaloneId,
+    });
+  });
+
+  assert.equal(current().workspaces.length, 2);
+  const freshWorkspace = current().workspaces.find((candidate) => candidate.id !== workspaceId);
+  assert.ok(freshWorkspace);
+  assert.notEqual(freshWorkspace.id, workspaceId);
+
+  await act(async () => {
+    renderer?.unmount();
+  });
+});

application/state/useShortcutModifierHeld.ts

@@ -1,4 +1,4 @@
-import { useEffect, useMemo, useState } from 'react';
+import { useEffect, useMemo, useSyncExternalStore } from 'react';
 
 import { parseKeyCombo, type HotkeyScheme } from '../../domain/models/keyBindings';
 
@@ -70,26 +70,55 @@ export function shouldReleaseShortcutModifier(
   return !isShortcutModifierHeld(event, requirements);
 }
 
-export function useShortcutModifierHeld(
+// The held flag lives in a tiny store so only the tab icon slots re-render when
+// it flips. It used to be TopTabs state, which re-rendered the whole tab bar
+// twice for every Ctrl/⌘ shortcut typed in a terminal (Ctrl+C, ⌘V, ...).
+let modifierHeld = false;
+const modifierHeldListeners = new Set<() => void>();
+
+function publishModifierHeld(next: boolean): void {
+  if (modifierHeld === next) return;
+  modifierHeld = next;
+  for (const listener of modifierHeldListeners) listener();
+}
+
+function subscribeModifierHeld(listener: () => void): () => void {
+  modifierHeldListeners.add(listener);
+  return () => {
+    modifierHeldListeners.delete(listener);
+  };
+}
+
+const getModifierHeld = () => modifierHeld;
+
+/** Whether the tab-switch modifier combination is currently held. */
+export function useShortcutModifierHeldValue(): boolean {
+  return useSyncExternalStore(subscribeModifierHeld, getModifierHeld, getModifierHeld);
+}
+
+/**
+ * Track the modifiers of the effective [1...9] tab-switch binding and publish
+ * whether they are held. Pass a null binding to stop tracking.
+ */
+export function useTrackShortcutModifierHeld(
   keyBinding: string | null,
   scheme: HotkeyScheme,
-): boolean {
-  const [isHeld, setIsHeld] = useState(false);
+): void {
   const requirements = useMemo(
     () => getShortcutModifierRequirements(keyBinding, scheme),
     [keyBinding, scheme],
   );
 
   useEffect(() => {
-    setIsHeld(false);
+    publishModifierHeld(false);
     if (!requirements) return;
 
     // Sync on every modifier transition so extras clear the preview and
     // releasing an extra modifier can re-arm when the exact combo remains.
     const syncHeldState = (event: KeyboardEvent) => {
-      setIsHeld(isShortcutModifierHeld(event, requirements));
+      publishModifierHeld(isShortcutModifierHeld(event, requirements));
     };
-    const clearHeldState = () => setIsHeld(false);
+    const clearHeldState = () => publishModifierHeld(false);
     const handleVisibilityChange = () => {
       if (document.visibilityState === 'hidden') {
         clearHeldState();
@@ -106,8 +135,7 @@ export function useShortcutModifierHeld(
       window.removeEventListener('keyup', syncHeldState, true);
       window.removeEventListener('blur', clearHeldState);
       document.removeEventListener('visibilitychange', handleVisibilityChange);
+      publishModifierHeld(false);
     };
   }, [requirements]);
-
-  return isHeld;
 }

application/state/useToolAccessGuidanceState.test.tsx

@@ -0,0 +1,81 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import React from 'react';
+import { act, create, type ReactTestRenderer } from 'react-test-renderer';
+import { useToolAccessGuidanceState, type ToolAccessGuidanceState } from './useToolAccessGuidanceState';
+import { AI_STATE_CHANGED_EVENT } from './aiStateEvents';
+import { STORAGE_KEY_AI_EXTERNAL_MCP_ENABLED } from '../../infrastructure/config/storageKeys';
+import type { AIToolIntegrationMode } from '../../infrastructure/ai/types';
+
+function deferred<T>() {
+  let resolve!: (value: T) => void;
+  const promise = new Promise<T>((done) => { resolve = done; });
+  return { promise, resolve };
+}
+async function harness() {
+  const requests: ReturnType<typeof deferred<unknown>>[] = [];
+  const events = new EventTarget();
+  const values = new Map([[STORAGE_KEY_AI_EXTERNAL_MCP_ENABLED, 'true']]);
+  const previous = new Map<string, PropertyDescriptor | undefined>();
+  const globals = {
+    IS_REACT_ACT_ENVIRONMENT: true,
+    localStorage: { getItem: (key: string) => values.get(key) ?? null, setItem: (key: string, value: string) => values.set(key, value) },
+    window: {
+      netcatty: {
+        externalMcpGetStatus: () => { const request = deferred<unknown>(); requests.push(request); return request.promise; },
+        aiSkillsCliGetInvocation: async () => ({ ok: true, skillPath: '/fixture/skills/SKILL.md', commandPrefix: 'fixture-cli' }),
+      },
+      addEventListener: events.addEventListener.bind(events), removeEventListener: events.removeEventListener.bind(events),
+      dispatchEvent: events.dispatchEvent.bind(events), setTimeout, clearTimeout,
+    },
+  };
+  for (const [key, value] of Object.entries(globals)) {
+    previous.set(key, Object.getOwnPropertyDescriptor(globalThis, key));
+    Object.defineProperty(globalThis, key, { value, configurable: true, writable: true });
+  }
+  let result!: ToolAccessGuidanceState;
+  function Harness({ mode }: { mode: AIToolIntegrationMode }) { result = useToolAccessGuidanceState(mode); return null; }
+  let renderer!: ReactTestRenderer;
+  await act(async () => { renderer = create(<Harness mode="mcp" />); });
+  return {
+    requests, events, values, result: () => result,
+    skills: async () => { await act(async () => renderer.update(<Harness mode="skills" />)); },
+    close: async () => {
+      await act(async () => renderer.unmount());
+      for (const [key, value] of previous) { if (value) Object.defineProperty(globalThis, key, value); else Reflect.deleteProperty(globalThis, key); }
+    },
+  };
+}
+const status = (path: string) => ({ ok: true, enabled: true, state: 'running', launcherPath: path, discoveryPath: `${path}.json` });
+
+test('older MCP guidance response cannot overwrite a newer enable-state refresh', async () => {
+  const h = await harness();
+  try {
+    assert.equal(h.requests.length, 1);
+    await act(async () => { h.events.dispatchEvent(new CustomEvent(AI_STATE_CHANGED_EVENT, { detail: { key: STORAGE_KEY_AI_EXTERNAL_MCP_ENABLED } })); });
+    assert.equal(h.requests.length, 2);
+    await act(async () => h.requests[1].resolve(status('/fixture/new')));
+    assert.equal(h.result().mcpLauncherPath, '/fixture/new');
+    await act(async () => h.requests[0].resolve(status('/fixture/old')));
+    assert.equal(h.result().mcpLauncherPath, '/fixture/new');
+  } finally { await h.close(); }
+});
+
+test('switching to Skills ignores pending MCP results and preserves resolved Skills guidance', async () => {
+  const h = await harness();
+  try {
+    await h.skills();
+    await act(async () => h.requests[0].resolve(status('/fixture/stale')));
+    assert.equal(h.result().mcpLauncherPath, null);
+    assert.equal(h.result().skillPath, '/fixture/skills/SKILL.md');
+    assert.equal(h.result().commandPrefix, 'fixture-cli');
+  } finally { await h.close(); }
+});
+
+test('MCP guidance completion after unmount has no visible state or retry work', async () => {
+  const h = await harness();
+  const initial = h.result();
+  await h.close();
+  await act(async () => h.requests[0].resolve(status('/fixture/stale')));
+  assert.equal(h.result(), initial);
+});

application/state/useToolAccessGuidanceState.ts

@@ -1,4 +1,4 @@
-import { useCallback, useEffect, useState } from 'react';
+import { useCallback, useEffect, useRef, useState } from 'react';
 import type { AIToolIntegrationMode } from '../../infrastructure/ai/types';
 import { STORAGE_KEY_AI_EXTERNAL_MCP_ENABLED } from '../../infrastructure/config/storageKeys';
 import { netcattyBridge } from '../../infrastructure/services/netcattyBridge';
@@ -38,14 +38,15 @@ export type ToolAccessGuidanceState = {
  * runtime is still starting or after an idle shutdown).
  */
 export function useToolAccessGuidanceState(mode: AIToolIntegrationMode): ToolAccessGuidanceState {
+  const requestGeneration = useRef(0);
   const [skillPath, setSkillPath] = useState<string | null>(null);
   const [commandPrefix, setCommandPrefix] = useState('');
   const [mcpLauncherPath, setMcpLauncherPath] = useState<string | null>(null);
   const [mcpDiscoveryPath, setMcpDiscoveryPath] = useState<string | null>(null);
 
-  const refreshMcpStatus = useCallback(async (): Promise<string | null | undefined> => {
+  const refreshMcpStatus = useCallback(async (isCurrent: () => boolean): Promise<string | null | undefined> => {
     const status = await netcattyBridge.get()?.externalMcpGetStatus?.();
-    if (!status?.ok) return undefined;
+    if (!isCurrent() || !status?.ok) return undefined;
     // Do not trust `enabled` alone: the main process flips `enabled` before
     // host credentials are resolved and the discovery file is written, and it
     // keeps reporting the configured discovery/launcher paths while starting.
@@ -93,9 +94,11 @@ export function useToolAccessGuidanceState(mode: AIToolIntegrationMode): ToolAcc
 
     const refetch = async () => {
       if (cancelled) return;
+      const generation = ++requestGeneration.current;
+      const isCurrent = () => !cancelled && generation === requestGeneration.current;
       const storedEnabled = readExternalMcpStoredEnabled();
-      const readyLauncherPath = await refreshMcpStatus().catch(() => undefined);
-      if (cancelled) return;
+      const readyLauncherPath = await refreshMcpStatus(isCurrent).catch(() => undefined);
+      if (!isCurrent()) return;
       // The persisted switch is off but the status check failed: drop any
       // cached launcher/discovery paths. The stored credentials were revoked
       // by the disable, and falling through to the comparison below would see

application/state/useToolbarItemLayout.ts

@@ -63,6 +63,9 @@ export function useToolbarItemLayout(
   const [layout, setLayout] = useState<ToolbarItemLayout>(() => readLayout(storageKey, defaults));
 
   useEffect(() => {
+    // Defaults can include dynamically discovered items; re-read without writing
+    // so temporary catalog changes never erase stored toolbar preferences.
+    setLayout(readLayout(storageKey, defaults));
     const sync = (event: Event) => {
       if (event instanceof StorageEvent && event.key !== storageKey) return;
       if (event instanceof CustomEvent && event.detail?.key !== storageKey) return;

application/state/useVaultAgentBridge.ts

@@ -55,6 +55,8 @@ export interface UseVaultAgentBridgeInput {
   openHost?: VaultAgentApiDeps['openHost'];
   findExistingSessionForHost?: VaultAgentApiDeps['findExistingSessionForHost'];
   closeSession?: VaultAgentApiDeps['closeSession'];
+  reconnectSession?: VaultAgentApiDeps['reconnectSession'];
+  inspectSessionRecovery?: VaultAgentApiDeps['inspectSessionRecovery'];
   getScriptSessionMeta?: (sessionId: string) => Pick<TerminalSession, 'status' | 'customName' | 'hostLabel' | 'hostname' | 'username'> | undefined;
 }
 
@@ -273,6 +275,8 @@ export function useVaultAgentBridge(input: UseVaultAgentBridgeInput): void {
           ? (host, isExternalMcpCall, options) => current.openHost!(host, isExternalMcpCall, options)
           : undefined,
         findExistingSessionForHost: current.findExistingSessionForHost,
+        reconnectSession: current.reconnectSession,
+        inspectSessionRecovery: current.inspectSessionRecovery,
         closeSession: current.closeSession
           ? (sessionId) => current.closeSession!(sessionId)
           : undefined,

application/state/useVaultState.shellHistory.test.ts

@@ -0,0 +1,63 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import React from "react";
+import { act, create, type ReactTestRenderer } from "react-test-renderer";
+import { JSDOM } from "jsdom";
+import { installBrowserLockFixture } from "../testSupport/browserLockFixture";
+import { STORAGE_KEY_SHELL_HISTORY } from "../../infrastructure/config/storageKeys";
+
+test("shell history append yields the input turn and persists merged entries", async () => {
+  const dom = new JSDOM("", { url: "http://localhost" });
+  const globals = ["window", "localStorage", "CustomEvent", "IS_REACT_ACT_ENVIRONMENT", "navigator"];
+  const previous = new Map(globals.map(key => [key, Object.getOwnPropertyDescriptor(globalThis, key)]));
+  Object.defineProperties(globalThis, {
+    window: { value: dom.window, configurable: true },
+    localStorage: { value: dom.window.localStorage, configurable: true },
+    CustomEvent: { value: dom.window.CustomEvent, configurable: true },
+    IS_REACT_ACT_ENVIRONMENT: { value: true, configurable: true },
+  });
+  installBrowserLockFixture();
+  const { useVaultState } = await import("./useVaultState");
+  let state: ReturnType<typeof useVaultState>;
+  let renderer: ReactTestRenderer | undefined;
+  const Probe = () => { state = useVaultState({ syncConnectionLogTerminalData: false }); return null; };
+  try {
+    await act(async () => { renderer = create(React.createElement(Probe)); });
+    for (let attempt = 0; !state!.isInitialized && attempt < 50; attempt++) {
+      await act(async () => { await new Promise(resolve => setTimeout(resolve, 10)); });
+    }
+    assert.equal(state!.isInitialized, true);
+    const entry = { command: " echo hello ", hostId: "local", hostLabel: "Local", sessionId: "one" };
+    act(() => {
+      state!.addShellHistoryEntry(entry);
+      state!.addShellHistoryEntry({ ...entry, sessionId: "two" });
+      assert.equal(dom.window.localStorage.getItem(STORAGE_KEY_SHELL_HISTORY), null);
+      assert.equal(state!.shellHistory.length, 0);
+    });
+    await act(async () => { await new Promise(resolve => setTimeout(resolve, 20)); });
+    const saved = JSON.parse(dom.window.localStorage.getItem(STORAGE_KEY_SHELL_HISTORY)!);
+    assert.equal(saved.length, 1);
+    assert.equal(saved[0].command, "echo hello");
+    assert.equal(saved[0].sessionId, "two");
+    assert.deepEqual(state!.shellHistory, saved);
+
+    for (const clear of [() => state!.clearShellHistory(), () => state!.clearAllCommandHistory()]) {
+      act(() => {
+        state!.addShellHistoryEntry(entry);
+        state!.addShellHistoryEntry({ ...entry, command: "another command" });
+        clear();
+      });
+      await act(async () => { await new Promise(resolve => setTimeout(resolve, 20)); });
+      assert.deepEqual(state!.shellHistory, []);
+      assert.deepEqual(JSON.parse(dom.window.localStorage.getItem(STORAGE_KEY_SHELL_HISTORY)!), []);
+    }
+  } finally {
+    await act(async () => { renderer?.unmount(); });
+    dom.window.close();
+    for (const key of globals) {
+      const descriptor = previous.get(key);
+      if (descriptor) Object.defineProperty(globalThis, key, descriptor);
+      else Reflect.deleteProperty(globalThis, key);
+    }
+  }
+});

application/state/useVaultState.ts

@@ -317,6 +317,7 @@ export const useVaultState = (options?: UseVaultStateOptions) => {
   const [noteGroups, setNoteGroups] = useState<string[]>([]);
   const [knownHosts, setKnownHosts] = useState<KnownHost[]>([]);
   const [shellHistory, setShellHistory] = useState<ShellHistoryEntry[]>([]);
+  const shellHistoryGenerationRef = useRef(0);
   const [connectionLogs, setConnectionLogs] = useState<ConnectionLog[]>([]);
   const [managedSources, setManagedSources] = useState<ManagedSource[]>([]);
   const [groupConfigs, setGroupConfigs] = useState<GroupConfig[]>([]);
@@ -1445,19 +1446,25 @@ export const useVaultState = (options?: UseVaultStateOptions) => {
 
   const addShellHistoryEntry = useCallback(
     (entry: Omit<ShellHistoryEntry, "id" | "timestamp">) => {
-      setShellHistory((prev) => {
-        const updated = mergeGlobalHistoryOnAppend(prev, entry);
-        if (updated === prev) return prev;
-        // Persist immediately so crash between commit and layout effect cannot drop history.
-        // Store republish is also done in useLayoutEffect for load/storage-event paths.
-        localStorageAdapter.write(STORAGE_KEY_SHELL_HISTORY, updated);
-        return updated;
-      });
+      const generation = shellHistoryGenerationRef.current;
+      // Yield the input turn before history rendering and synchronous storage work.
+      // Persist in the next task to keep the crash-loss window small.
+      setTimeout(() => {
+        if (generation !== shellHistoryGenerationRef.current) return;
+        setShellHistory((prev) => {
+          if (generation !== shellHistoryGenerationRef.current) return prev;
+          const updated = mergeGlobalHistoryOnAppend(prev, entry);
+          if (updated === prev) return prev;
+          localStorageAdapter.write(STORAGE_KEY_SHELL_HISTORY, updated);
+          return updated;
+        });
+      }, 0);
     },
     [],
   );
 
   const clearShellHistory = useCallback(() => {
+    shellHistoryGenerationRef.current += 1;
     setShellHistory([]);
     localStorageAdapter.write(STORAGE_KEY_SHELL_HISTORY, []);
     publishShellHistorySnapshot([]);

application/state/useWorkspaceLayoutPresetState.test.tsx

@@ -1,7 +1,7 @@
 import assert from 'node:assert/strict';
 import test from 'node:test';
 import React from 'react';
-import { act, create, type ReactTestRenderer } from 'react-test-renderer';
+import { act, create } from 'react-test-renderer';
 
 import {
   collectSidePanelPanes,

application/syncPayload.aiSessions.test.ts

@@ -79,6 +79,17 @@ test('sync persistence survives restart beyond the local-only history limits', (
   assert.equal(localOnly[0].messages.length, 200);
 });
 
+test('sync collection after restart includes overflow before clearing it', () => {
+  const primary = session();
+  const overflow = { ...session(), id: 'overflow-chat', updatedAt: 1 };
+  save([primary], true);
+  storage.set(keys.STORAGE_KEY_AI_SESSIONS_OVERFLOW, JSON.stringify([overflow]));
+  snapshots.setLatestAISessionsSnapshot(null as unknown as AISession[]);
+  assert.deepEqual(collectAiSessionsForSync()?.map(value => value.id), [primary.id, overflow.id]);
+  assert.equal(storage.has(keys.STORAGE_KEY_AI_SESSIONS_OVERFLOW), false);
+  assert.deepEqual(JSON.parse(storage.get(keys.STORAGE_KEY_AI_SESSIONS)!).map((value: AISession) => value.id), [primary.id, overflow.id]);
+});
+
 test('failed history persistence refuses upload without pruning the cloud representation', async () => {
   save([session()]);
   const original = globalThis.localStorage.setItem;
@@ -208,13 +219,15 @@ test('replacement stops active turns and waits for finalizers before persisting
       globalThis.localStorage.setItem = (key, value) => { if (key === keys.STORAGE_KEY_AI_SESSIONS) order.push('persist'); original(key, value); };
       const incoming = { ...session(), updatedAt: 3, messages: [...session().messages,
         { id: 'remote', role: 'user' as const, content: 'Remote', timestamp: 3 }] };
-      await applySyncPayload(remotePayload(remove ? [] : [incoming]), { importVaultData: () => undefined });
+      await applyLocalVaultPayload(remotePayload(remove ? [] : [incoming]), { importVaultData: () => undefined }, {
+        prepareConvergentRestore: async () => async () => {},
+      });
       assert.ok(order.indexOf('cancel') < order.indexOf('settled'));
       assert.ok(order.indexOf('settled') < order.indexOf('persist'));
       assert.ok(order.indexOf('persist') < order.indexOf('cleanup'));
       assert.equal(hook!.abortControllersRef.current.has('chat'), false);
       if (remove) assert.deepEqual(getAISessionsSnapshot().sessions, []);
-      else assert.ok(getAISessionsSnapshot().sessions[0].messages.some(message => message.content === 'Settled'));
+      else assert.equal(getAISessionsSnapshot().sessions[0].messages.at(-1)?.content, 'Remote');
       wait.mock.restore();
       globalThis.localStorage.setItem = original;
       await act(async () => { hook!.setStreamingForScope('chat', false); });
@@ -226,6 +239,44 @@ test('replacement stops active turns and waits for finalizers before persisting
   }
 });
 
+test('cloud sync preserves an active trimmed conversation and its native thread', async () => {
+  Object.assign(globalThis, { IS_REACT_ACT_ENVIRONMENT: true });
+  let hook: UseAIChatStreamingReturn;
+  function Harness() {
+    hook = useAIChatStreaming({ maxIterations: 1, addMessageToSession: () => {}, updateLastMessage: () => {}, updateMessageById: () => {} });
+    return null;
+  }
+  let renderer: ReactTestRenderer;
+  await act(async () => { renderer = create(React.createElement(Harness)); });
+  const calls: string[] = [];
+  const controller = new AbortController();
+  const messages = Array.from({ length: 501 }, (_, i) => ({ id: `m-${i}`, role: 'user' as const, content: `Message ${i}`, timestamp: i }));
+  const remote = { ...session(), agentId: 'codex', messages };
+  // Appending the 501st message trims the oldest message locally.
+  const local = { ...remote, messages: messages.slice(-500), externalSessionId: 'native-thread' };
+  save([local]);
+  hook!.abortControllersRef.current.set('chat', controller);
+  await act(async () => { hook!.setStreamingForScope('chat', true); });
+  Object.assign(window, { netcatty: {
+    aiCattyCancelExec: async () => { calls.push('cancel'); },
+    aiSdkAgentCancel: async () => { calls.push('sdk-cancel'); return { ok: true }; },
+    aiSdkAgentCleanup: async () => { calls.push('cleanup'); return { ok: true }; },
+  } });
+  try {
+    for (const incoming of [[remote], []]) {
+      await applySyncPayload(remotePayload(incoming), { importVaultData: () => undefined });
+      assert.equal(controller.signal.aborted, false);
+      assert.deepEqual(calls, []);
+      assert.deepEqual(getAISessionsSnapshot().sessions, [local]);
+      assert.equal(JSON.parse(storage.get(keys.STORAGE_KEY_AI_SESSIONS)!)[0].externalSessionId, 'native-thread');
+    }
+  } finally {
+    hook!.abortControllersRef.current.delete('chat');
+    await act(async () => { hook!.setStreamingForScope('chat', false); renderer!.unmount(); });
+    delete (window as unknown as { netcatty?: unknown }).netcatty;
+  }
+});
+
 test('local restore replaces later sessions and later turns with the backup snapshot', async () => {
   const backedUp = session();
   const later = { ...session(), updatedAt: 3, messages: [...session().messages,

application/syncPayload.ts

@@ -51,6 +51,7 @@ import { sanitizeQuickMessages } from '../infrastructure/ai/quickMessages';
 import { emitAIStateChanged } from './state/aiStateEvents';
 import {
   latestAISessionsSnapshot,
+  readSessionsFromStorage,
   setLatestAISessionsSnapshot,
   writeSessionsForStorage,
   cleanupSdkAgentSessions,
@@ -1073,8 +1074,7 @@ export function collectAiSessionsForSync(): SyncPayload['aiSessions'] {
 
 function collectLocalAiSessions(): NonNullable<SyncPayload['aiSessions']> {
   return latestAISessionsSnapshot
-    ?? localStorageAdapter.read<SyncPayload['aiSessions']>(STORAGE_KEY_AI_SESSIONS)
-    ?? [];
+    ?? readSessionsFromStorage();
 }
 
 /** Build the portable payload; device-local data is added by the backup builder. */
@@ -1275,6 +1275,8 @@ export async function buildLocalVaultPayloadAsync(
 
 /** Merge downloaded chat data through the existing state and persistence boundary. */
 async function applyAiSessionData(sessions: NonNullable<SyncPayload['aiSessions']>, includeLocalOnlyData: boolean): Promise<void> {
+  const { isAIChatSessionStreaming, stopAIChatSessionBeforeReplacement } = await import('./state/useAIChatStreaming');
+  const preserveActive = (id: string) => !includeLocalOnlyData && isAIChatSessionStreaming(id);
   const incoming = includeLocalOnlyData
     ? sessions
     : sessions.map(stripAiSessionDeviceState);
@@ -1282,26 +1284,29 @@ async function applyAiSessionData(sessions: NonNullable<SyncPayload['aiSessions'
   const incomingById = new Map(incoming.map((session) => [session.id, session]));
   const portableMessages = (value: typeof incoming[number]) => stripAiSessionPayloadForSync([value])[0].messages;
   const affectedIds = collectLocalAiSessions().filter((local) => {
+    if (preserveActive(local.id)) return false;
     const next = incomingById.get(local.id);
     if (!next) return true;
     const candidate = includeLocalOnlyData ? next : mergeAiSessionLists([local], [next])[0];
     return JSON.stringify(portableMessages(local)) !== JSON.stringify(portableMessages(candidate));
   }).map((session) => session.id);
   if (affectedIds.length > 0) {
-    const { stopAIChatSessionBeforeReplacement } = await import('./state/useAIChatStreaming');
     await Promise.all(affectedIds.map(stopAIChatSessionBeforeReplacement));
   }
   // Stop finalizers can finish the last local message. Read it again before
   // merging so the stopped turn cannot write into a replaced/deleted session.
   const localSessions = collectLocalAiSessions();
   const localById = new Map(localSessions.map((session) => [session.id, session]));
-  const removedIds = localSessions.filter((session) => !incomingIds.has(session.id)).map((session) => session.id);
+  const removedIds = localSessions.filter((session) => !incomingIds.has(session.id) && !preserveActive(session.id)).map((session) => session.id);
   const resetSdkSessions: string[] = [];
   // The sync merge has already decided which session IDs survive. Backups
   // restore their exact transcript; cloud survivors still retain local turns.
   const candidates = includeLocalOnlyData ? incoming
     : mergeAiSessionLists(localSessions.filter((session) => incomingIds.has(session.id)), incoming);
-  const mergedSessions = candidates.map((session) => {
+  // Keep active cloud sessions intact until a later sync, including remote deletions.
+  const retainedActive = localSessions.filter((session) => preserveActive(session.id));
+  const mergedSessions = [...candidates.filter((session) => !preserveActive(session.id)), ...retainedActive].map((session) => {
+    if (preserveActive(session.id)) return session;
     // Native SDK threads belong to this device. Reuse the local thread
     // only while it already contains the entire merged transcript.
     const local = localById.get(session.id);

components/AIChatPanelContent.test.ts

@@ -40,3 +40,35 @@ test('terminal side panel tools share one primary toolbar height', () => {
     assert.match(source, /TERMINAL_SIDE_PANEL_INNER_HEADER_CLASS/);
   }
 });
+
+test('/rename and /chats panel commands stay out of the agent message path', () => {
+  const sidePanel = preparingSource;
+  // Panel implements the commands with updateSessionTitle + a note state —
+  // never addMessageToSession, so the commands cannot leak into chat history.
+  assert.match(sidePanel, /handleRenameSession = useCallback/);
+  assert.match(sidePanel, /handleListChats = useCallback/);
+  assert.match(sidePanel, /updateSessionTitle\(sessionId, title\)/);
+  assert.match(sidePanel, /setPanelCommandNote\(formatAiChatsListingNote\(entries, t\)\)/);
+  const renameHandler = sidePanel.slice(
+    sidePanel.indexOf('handleRenameSession = useCallback'),
+    sidePanel.indexOf('const handleRenameSlashCommand'),
+  );
+  assert.doesNotMatch(renameHandler, /addMessageToSession/);
+  const chatsHandler = sidePanel.slice(
+    sidePanel.indexOf('handleListChats = useCallback'),
+    sidePanel.indexOf('const handleSend'),
+  );
+  assert.doesNotMatch(chatsHandler, /addMessageToSession/);
+  // Wiring reaches AIChatPanelContent.
+  assert.match(sidePanel, /onRenameActiveChat=\{handleRenameSlashCommand\}/);
+  assert.match(sidePanel, /onListChats=\{handleListChats\}/);
+});
+
+test('AIChatPanelContent renders the panel command note and wires rename/list props', () => {
+  assert.match(panelSource, /panelCommandNote \? \(/);
+  assert.match(panelSource, /role="status"/);
+  assert.match(panelSource, /onDismissPanelCommandNote/);
+  assert.match(panelSource, /onRenameSession=\{onRenameActiveChat\}/);
+  assert.match(panelSource, /onListChats=\{onListChats\}/);
+  assert.match(panelSource, /onRename=\{onRenameSession\}/);
+});

components/AIChatPanelContent.tsx

@@ -57,6 +57,20 @@ interface AIChatPanelContentProps {
   setInputValue: (value: string) => void;
   handleSend: () => void;
   handleCompact: () => void;
+  /** Rename a chat by id (history drawer edit affordance). Panel action, never agent content. */
+  onRenameSession?: (sessionId: string, title: string) => void;
+  /** `/rename <title>` for the current chat. Panel action, never agent content. */
+  onRenameActiveChat?: (title: string) => void;
+  /** `/chats`: list the chats visible to this panel. Panel action, never agent content. */
+  onListChats?: () => void;
+  /** `/rebind <n>`: rebind a dangling chat to this panel's scope. Panel action, never agent content. */
+  onRebindChat?: (arg: string) => void;
+  /** `/chats` listing output, rendered as a system-style note above the composer. */
+  panelCommandNote?: string | null;
+  onDismissPanelCommandNote?: () => void;
+  /** Manual durability escape hatch: export/import the whole session store. */
+  onExportSessions?: () => void;
+  onImportSessions?: () => void;
   /** Undo last turn is offered at a safe boundary (never mid-tool / mid-compaction). */
   canUndoLastTurn?: boolean;
   handleUndoLastTurn?: () => void;
@@ -142,6 +156,14 @@ export const AIChatPanelContent: React.FC<AIChatPanelContentProps> = ({
   setInputValue,
   handleSend,
   handleCompact,
+  onRenameSession,
+  onRenameActiveChat,
+  onListChats,
+  onRebindChat,
+  panelCommandNote,
+  onDismissPanelCommandNote,
+  onExportSessions,
+  onImportSessions,
   canUndoLastTurn = false,
   handleUndoLastTurn,
   canCompact = false,
@@ -309,6 +331,9 @@ export const AIChatPanelContent: React.FC<AIChatPanelContentProps> = ({
             activeSessionId={activeSessionId}
             onSelect={sending ? () => undefined : handleSelectSession}
             onDelete={handleDeleteSession}
+            onRename={onRenameSession}
+            onExportSessions={onExportSessions}
+            onImportSessions={onImportSessions}
             onClose={() => setShowHistory(false)}
           />
         </React.Profiler>
@@ -369,6 +394,21 @@ export const AIChatPanelContent: React.FC<AIChatPanelContentProps> = ({
           {!hideInput && (
             <React.Profiler {...getAIPanelProfilerProps('AIChatPanel.Input')}>
               <div>
+                {panelCommandNote ? (
+                  <div role="status" className="mx-3 mb-1.5 rounded-md border border-border/50 bg-muted/30 px-2.5 py-1.5 text-[11px] leading-4 text-muted-foreground">
+                    <span className="block max-h-48 overflow-y-auto whitespace-pre-wrap break-words">{panelCommandNote}</span>
+                    {onDismissPanelCommandNote && (
+                      <button
+                        type="button"
+                        aria-label={t('common.close')}
+                        onClick={onDismissPanelCommandNote}
+                        className="mt-1 text-[11px] text-muted-foreground/60 underline-offset-2 transition-colors hover:text-foreground hover:underline cursor-pointer"
+                      >
+                        {t('common.close')}
+                      </button>
+                    )}
+                  </div>
+                ) : null}
                 {steerWarning ? (
                   <div role="status" className="mx-3 mb-1.5 rounded-md border border-amber-500/25 bg-amber-500/10 px-2.5 py-1.5 text-[11px] leading-4 text-amber-600 dark:text-amber-400">
                     {steerWarning}
@@ -396,6 +436,9 @@ export const AIChatPanelContent: React.FC<AIChatPanelContentProps> = ({
                   onChange={setInputValue}
                   onSend={handleSend}
                   onCompact={handleCompact}
+                  onRenameSession={onRenameActiveChat}
+                  onListChats={onListChats}
+                  onRebindChat={onRebindChat}
                   canCompact={canCompact}
                   onSteer={handleSteer}
                   onStop={handleStop}

components/AIChatSessionHistoryDrawer.test.tsx

@@ -3,7 +3,7 @@ import test from "node:test";
 import React from "react";
 
 import type { AISession } from "../infrastructure/ai/types.ts";
-import { MESSAGES_BY_LOCALE } from "../application/i18n/messages.ts";
+import { getLoadedLocaleMessages, loadLocaleMessages } from "../application/i18n/messages.ts";
 import { createDomRenderer, dispatchDomEvent, installDomEnvironment, runWithAct } from "./test-support/renderReactDom.tsx";
 
 test("history drawer filters, pages, clears and explains the bounded search in every locale", async () => {
@@ -107,9 +107,11 @@ test("history drawer filters, pages, clears and explains the bounded search in e
     assert.equal(closed, 1);
 
     for (const locale of ["en", "zh-CN", "zh-TW", "es", "ru"]) {
+      // Non-English dictionaries load on demand.
+      await loadLocaleMessages(locale);
       await render(sessions, locale);
       await enterQuery("no-such-content");
-      const messages = MESSAGES_BY_LOCALE[locale];
+      const messages = getLoadedLocaleMessages(locale)!;
       const input = renderer.container.querySelector("input")!;
       const hint = dom.document.getElementById(input.getAttribute("aria-describedby")!);
       for (const key of ["ai.chat.searchSessions", "ai.chat.searchSessionsHint", "ai.chat.noMatchingSessions"]) {

components/AIChatSessionHistoryDrawer.tsx

@@ -1,5 +1,5 @@
 import React, { useEffect, useId, useRef, useState } from 'react';
-import { Search, Trash2, X } from 'lucide-react';
+import { Download, Pencil, Search, Trash2, Upload, X } from 'lucide-react';
 import type { AISession } from '../infrastructure/ai/types';
 import { useI18n } from '../application/i18n/I18nProvider';
 import { cn } from '../lib/utils';
@@ -19,6 +19,12 @@ interface SessionHistoryDrawerProps {
   activeSessionId: string | null;
   onSelect: (sessionId: string) => void;
   onDelete: (e: React.MouseEvent, sessionId: string) => void;
+  /** Rename a chat inline (issue #4015 R5). Empty titles are ignored. */
+  onRename?: (sessionId: string, title: string) => void;
+  /** Manual durability escape hatch: export the whole store to a JSON file. */
+  onExportSessions?: () => void;
+  /** Import sessions from a JSON export; merges by id, newer wins. */
+  onImportSessions?: () => void;
   onClose: () => void;
 }
 
@@ -30,11 +36,17 @@ export const SessionHistoryDrawer: React.FC<SessionHistoryDrawerProps> = ({
   activeSessionId,
   onSelect,
   onDelete,
+  onRename,
+  onExportSessions,
+  onImportSessions,
   onClose,
 }) => {
   const { t } = useI18n();
   const [renderCount, setRenderCount] = useState(SESSION_RENDER_BATCH);
   const [searchQuery, setSearchQuery] = useState('');
+  const [renamingSessionId, setRenamingSessionId] = useState<string | null>(null);
+  const [renameDraft, setRenameDraft] = useState('');
+  const renameInputRef = useRef<HTMLInputElement>(null);
   const searchHintId = useId();
   const searchInputRef = useRef<HTMLInputElement>(null);
   const { filteredSessions, isSearching } = useSessionHistorySearch(
@@ -52,16 +64,69 @@ export const SessionHistoryDrawer: React.FC<SessionHistoryDrawerProps> = ({
   const displayedSessions = filteredSessions.slice(0, renderCount);
   const hiddenSessionCount = Math.max(0, filteredSessions.length - renderCount);
 
+  useEffect(() => {
+    if (renamingSessionId) renameInputRef.current?.focus();
+  }, [renamingSessionId]);
+
+  const beginRename = (sessionId: string, currentTitle: string) => {
+    setRenamingSessionId(sessionId);
+    setRenameDraft(currentTitle);
+  };
+
+  const commitRename = () => {
+    if (renamingSessionId && renameDraft.trim()) {
+      onRename?.(renamingSessionId, renameDraft.trim());
+    }
+    setRenamingSessionId(null);
+    setRenameDraft('');
+  };
+
   return (
     <div className="flex-1 flex flex-col min-h-0">
       <div className="px-4 py-2.5 flex items-center justify-between shrink-0 border-b border-border/30">
         <span className="text-[13px] font-medium text-foreground/80">{t('ai.chat.allSessions')}</span>
-        <button
-          onClick={onClose}
-          className="text-[12px] text-muted-foreground/60 hover:text-muted-foreground transition-colors cursor-pointer"
-        >
-          <X size={14} />
-        </button>
+        <div className="flex items-center gap-2">
+          {onImportSessions && (
+            <Tooltip>
+              <TooltipTrigger asChild>
+                <button
+                  onClick={(e) => {
+                    e.stopPropagation();
+                    onImportSessions();
+                  }}
+                  className="text-[12px] text-muted-foreground/60 hover:text-muted-foreground transition-colors cursor-pointer"
+                  aria-label={t('ai.chat.importSessions')}
+                >
+                  <Upload size={14} />
+                </button>
+              </TooltipTrigger>
+              <TooltipContent>{t('ai.chat.importSessions')}</TooltipContent>
+            </Tooltip>
+          )}
+          {onExportSessions && (
+            <Tooltip>
+              <TooltipTrigger asChild>
+                <button
+                  onClick={(e) => {
+                    e.stopPropagation();
+                    onExportSessions();
+                  }}
+                  className="text-[12px] text-muted-foreground/60 hover:text-muted-foreground transition-colors cursor-pointer"
+                  aria-label={t('ai.chat.exportSessions')}
+                >
+                  <Download size={14} />
+                </button>
+              </TooltipTrigger>
+              <TooltipContent>{t('ai.chat.exportSessions')}</TooltipContent>
+            </Tooltip>
+          )}
+          <button
+            onClick={onClose}
+            className="text-[12px] text-muted-foreground/60 hover:text-muted-foreground transition-colors cursor-pointer"
+          >
+            <X size={14} />
+          </button>
+        </div>
       </div>
       <div className="px-3 py-2 shrink-0 border-b border-border/30">
         <div className="relative">
@@ -146,12 +211,52 @@ export const SessionHistoryDrawer: React.FC<SessionHistoryDrawerProps> = ({
                   )}
                 >
                   <span className={SESSION_HISTORY_ROW_CLASSNAMES.title}>
-                    {session.title || t('ai.chat.untitled')}
+                    {renamingSessionId === session.id ? (
+                      <Input
+                        ref={renameInputRef}
+                        type="text"
+                        value={renameDraft}
+                        aria-label={t('ai.chat.renameChat')}
+                        onClick={(e) => e.stopPropagation()}
+                        onKeyDown={(e) => {
+                          e.stopPropagation();
+                          if (e.key === 'Enter') {
+                            e.preventDefault();
+                            commitRename();
+                          } else if (e.key === 'Escape') {
+                            e.preventDefault();
+                            setRenamingSessionId(null);
+                            setRenameDraft('');
+                          }
+                        }}
+                        onChange={(e) => setRenameDraft(e.target.value)}
+                        onBlur={commitRename}
+                        className="h-6 text-[12px]"
+                      />
+                    ) : (
+                      session.title || t('ai.chat.untitled')
+                    )}
                   </span>
                   <div className={SESSION_HISTORY_ROW_CLASSNAMES.meta}>
                     <span className={SESSION_HISTORY_ROW_CLASSNAMES.time}>
                       {timeStr}
                     </span>
+                    {onRename && renamingSessionId !== session.id && (
+                      <Tooltip>
+                        <TooltipTrigger asChild>
+                          <button
+                            onClick={(e) => {
+                              e.stopPropagation();
+                              beginRename(session.id, session.title || '');
+                            }}
+                            className={SESSION_HISTORY_ROW_CLASSNAMES.deleteButton}
+                          >
+                            <Pencil size={12} />
+                          </button>
+                        </TooltipTrigger>
+                        <TooltipContent>{t('ai.chat.renameChat')}</TooltipContent>
+                      </Tooltip>
+                    )}
                     <Tooltip>
                       <TooltipTrigger asChild>
                         <button