Merge branch 'integration/plugin-capabilities-ui' into feat/plugin-vault-pages

# Conflicts:
#	electron/plugins/hostService.cjs
#	packages/plugin-cli/src/manifest.ts
#	packages/plugin-contract/src/index.ts
#	packages/plugin-sdk/src/index.ts

application/i18n/locales/en/core.ts

@@ -1246,6 +1246,9 @@ Highlight the focused split pane:
   "settings.plugins.manager.remove": "Uninstall",
   "settings.plugins.manager.removeNote": "Uninstall removes package code and local KV data. User-owned settings, secrets and sync sidecars are retained.",
   "settings.plugins.permissions.statusUnknown": "Status unknown",
+  "plugins.vault.loading": "Loading plugin page…",
+  "plugins.vault.extensions": "Extensions",
+  "plugins.vault.back": "Back to hosts",
   "plugins.interaction.title": "Plugin request",
   "plugins.interaction.sharing": "Text you share becomes available to this plugin and its granted capabilities, including network access. Reading does not approve a new network destination.",
   "plugins.interaction.input": "Input text",

application/i18n/locales/es/core.ts

@@ -1246,6 +1246,9 @@ Resalta el panel dividido enfocado:
   "settings.plugins.manager.remove": "Desinstalar",
   "settings.plugins.manager.removeNote": "La desinstalación elimina el código y los datos KV locales. Se conservan los ajustes del usuario, los secretos y los datos auxiliares de sincronización.",
   "settings.plugins.permissions.statusUnknown": "Estado desconocido",
+  "plugins.vault.loading": "Cargando página del plugin…",
+  "plugins.vault.extensions": "Extensiones",
+  "plugins.vault.back": "Volver a hosts",
   "plugins.interaction.title": "Solicitud de complemento",
   "plugins.interaction.sharing": "El texto compartido estará disponible para este complemento y sus capacidades autorizadas, incluida la red. Leer no autoriza un nuevo destino de red.",
   "plugins.interaction.input": "Introducir texto",

application/i18n/locales/ru/core.ts

@@ -1141,6 +1141,9 @@ export const ruCoreMessages: Messages = {
   "settings.plugins.manager.remove": "Удалить",
   "settings.plugins.manager.removeNote": "Удаление очищает код пакета и локальные данные KV. Настройки пользователя, секреты и данные синхронизации сохраняются.",
   "settings.plugins.permissions.statusUnknown": "Состояние неизвестно",
+  "plugins.vault.loading": "Загрузка страницы плагина…",
+  "plugins.vault.extensions": "Расширения",
+  "plugins.vault.back": "К хостам",
   "plugins.interaction.title": "Запрос плагина",
   "plugins.interaction.sharing": "Переданный текст доступен плагину и его разрешённым возможностям, включая сеть. Чтение не разрешает новый сетевой адрес.",
   "plugins.interaction.input": "Ввести текст",

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

@@ -1161,6 +1161,9 @@ Vaults 标签保持扁平，不使用这块背景。
   "settings.plugins.manager.remove": "卸载",
   "settings.plugins.manager.removeNote": "卸载会移除插件代码和本地 KV 数据，保留用户设置、秘密存储和同步 sidecar。",
   "settings.plugins.permissions.statusUnknown": "状态未知",
+  "plugins.vault.loading": "正在加载插件页面…",
+  "plugins.vault.extensions": "扩展",
+  "plugins.vault.back": "返回主机",
   "plugins.interaction.title": "插件请求",
   "plugins.interaction.sharing": "分享的文本将交给此插件及其已授权的能力（包括网络访问）。读取文本不代表批准新的网络目标。",
   "plugins.interaction.input": "输入文本",

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

@@ -1164,6 +1164,9 @@ Vaults 分頁維持扁平，不使用這塊背景。
   "settings.plugins.manager.remove": "卸載",
   "settings.plugins.manager.removeNote": "卸載會移除插件代碼和本地 KV 數據，保留用戶設置、秘密存儲和同步 sidecar。",
   "settings.plugins.permissions.statusUnknown": "狀態不明",
+  "plugins.vault.loading": "正在載入擴充功能頁面…",
+  "plugins.vault.extensions": "擴充功能",
+  "plugins.vault.back": "返回主機",
   "plugins.interaction.title": "外掛請求",
   "plugins.interaction.sharing": "分享的文字會交給此外掛及其已授權能力（包括網路存取）。讀取文字不代表核准新的網路目的地。",
   "plugins.interaction.input": "輸入文字",

application/state/pluginVaultPages.ts

@@ -0,0 +1,27 @@
+export const PLUGIN_VAULT_PAGE_PREFIX = 'plugin-vault:';
+
+export interface PluginVaultPage {
+  key: `plugin-vault:${string}`;
+  pluginId: string;
+  pluginName: string;
+  version: string;
+  viewId: string;
+  title: string;
+  icon?: NetcattyPluginIconReference;
+  order: number;
+}
+
+export function collectPluginVaultPages(plugins: NetcattyPluginContributionSnapshot['plugins']): PluginVaultPage[] {
+  return plugins.flatMap((plugin) => plugin.views
+    .filter((view) => view.location === 'vault-page' && view.visible)
+    .map((view): PluginVaultPage => ({
+      key: `${PLUGIN_VAULT_PAGE_PREFIX}${view.id}`,
+      pluginId: plugin.id, pluginName: plugin.displayName, version: plugin.version,
+      viewId: view.id, title: view.title, icon: view.icon, order: view.order ?? 0,
+    })))
+    .sort((left, right) => left.order - right.order || left.viewId.localeCompare(right.viewId));
+}
+
+export function resolvePluginVaultPage(pages: readonly PluginVaultPage[], section: string): PluginVaultPage | null {
+  return pages.find((page) => page.key === section) ?? null;
+}

application/state/pluginViewOcclusion.ts

@@ -0,0 +1,18 @@
+/** Native child views must yield to host dialogs and overlapping portals. */
+export function isPluginViewOccluded(mount: HTMLElement): boolean {
+  const rect = mount.getBoundingClientRect();
+  if (!mount.isConnected || mount.closest('[hidden], [inert]')) return true;
+  const overlays = mount.ownerDocument.querySelectorAll(
+    '[data-app-lock-overlay], [role="dialog"], [role="alertdialog"], '
+    + '[role="menu"][data-state="open"], [data-radix-popper-content-wrapper] > *, [data-native-view-occluder]',
+  );
+  return [...overlays].some((overlay) => {
+    if (mount.contains(overlay)) return false;
+    const style = getComputedStyle(overlay);
+    if (style.display === 'none' || style.visibility === 'hidden' || overlay.closest('[hidden], [inert]')) return false;
+    if (overlay.matches('[data-app-lock-overlay], [role="dialog"][aria-modal="true"], [role="alertdialog"]')) return true;
+    const other = overlay.getBoundingClientRect();
+    return other.width > 0 && other.height > 0 && other.x < rect.right && other.right > rect.x
+      && other.y < rect.bottom && other.bottom > rect.y;
+  });
+}

application/state/useEmbeddedPluginView.ts

@@ -0,0 +1,99 @@
+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' | 'setViewBounds' | 'setViewVisibility' | 'onViewClosed'>;
+
+/** Host-owned mounting only. No plugin router, DOM, session or vault data API. */
+export function useEmbeddedPluginView({ viewId, version, slot, active, context, adapter, subscribeHidden, unavailable }: {
+  viewId: string;
+  version: string;
+  slot: string;
+  active: boolean;
+  context: Record<string, unknown>;
+  adapter: ViewAdapter;
+  subscribeHidden(listener: () => void): () => void;
+  unavailable(): void;
+}) {
+  const mountRef = useRef<HTMLDivElement>(null);
+  const [loading, setLoading] = useState(true);
+  const adapterRef = useRef(adapter);
+  const unavailableRef = useRef(unavailable);
+  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, setViewBounds, setViewVisibility, onViewClosed } = 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 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 visible = false;
+    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).catch(failCurrent);
+    };
+    const resize = () => {
+      if (opened && !cancelled) void setViewBounds(instanceId, bounds()).catch(failCurrent);
+      updateVisibility();
+    };
+    const observer = typeof ResizeObserver === 'undefined' ? null : new ResizeObserver(resize);
+    observer?.observe(mount);
+    const mutations = new MutationObserver(updateVisibility);
+    mutations.observe(document.body, { childList: true, subtree: true, attributes: true,
+      attributeFilter: ['class', 'style', 'hidden', 'inert', 'role', 'aria-modal', 'data-state', 'data-app-lock-overlay', '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(); observer?.disconnect(); mutations.disconnect();
+      window.removeEventListener('resize', resize); document.removeEventListener('scroll', resize, true);
+    };
+  }, [active, context, slot, subscribeHidden, version, viewId]);
+  return { mountRef, loading };
+}

application/state/usePluginVaultPages.ts

@@ -0,0 +1,47 @@
+import { useCallback, useEffect, useMemo, useRef } from 'react';
+import { activeTabStore, useActiveTabId } from './activeTabStore';
+import { collectPluginVaultPages, PLUGIN_VAULT_PAGE_PREFIX, resolvePluginVaultPage } from './pluginVaultPages';
+import { usePluginContributions } from './usePluginContributions';
+import { OPEN_PLUGIN_VIEW_EVENT, type OpenPluginViewDetail } from './usePluginViewLifecycle';
+
+const CONTEXT = Object.freeze({ 'netcatty.surface': 'vault-page' });
+
+export function usePluginVaultPages({ locale, section, select }: {
+  locale: string;
+  section: string;
+  select(section: 'hosts' | `plugin-vault:${string}`): void;
+}) {
+  const active = useActiveTabId() === 'vault';
+  const sectionRef = useRef(section);
+  const focusFrame = useRef<number | null>(null);
+  sectionRef.current = section;
+  useEffect(() => () => { if (focusFrame.current !== null) cancelAnimationFrame(focusFrame.current); }, []);
+  const contributions = usePluginContributions({ locale, context: CONTEXT });
+  const pages = useMemo(() => collectPluginVaultPages(contributions.snapshot.plugins), [contributions.snapshot.plugins]);
+  const selected = resolvePluginVaultPage(pages, section);
+  const fallback = useCallback(() => {
+    select('hosts');
+    if (focusFrame.current !== null) cancelAnimationFrame(focusFrame.current);
+    focusFrame.current = requestAnimationFrame(() => {
+      focusFrame.current = null;
+      if (sectionRef.current === 'hosts' && activeTabStore.getActiveTabId() === 'vault') {
+        document.querySelector<HTMLButtonElement>('[data-plugin-vault-fallback]')?.focus();
+      }
+    });
+  }, [select]);
+  useEffect(() => {
+    if (!contributions.loading && section.startsWith(PLUGIN_VAULT_PAGE_PREFIX) && !selected) fallback();
+  }, [contributions.loading, fallback, section, selected]);
+  useEffect(() => {
+    const open = (event: Event) => {
+      const detail = (event as CustomEvent<OpenPluginViewDetail>).detail;
+      const page = pages.find((item) => item.viewId === detail?.viewId);
+      if (!page) return;
+      activeTabStore.setActiveTabId('vault');
+      select(page.key);
+    };
+    window.addEventListener(OPEN_PLUGIN_VIEW_EVENT, open);
+    return () => window.removeEventListener(OPEN_PLUGIN_VIEW_EVENT, open);
+  }, [pages, select]);
+  return { pages, selected, active, select, fallback, contributions, context: CONTEXT };
+}

application/state/usePluginViewLifecycle.ts

@@ -82,7 +82,7 @@ export function usePluginViewLifecycle({
   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) ?? null,
+    .find(({ view }) => view.id === effectiveRequested?.viewId && view.visible && view.location !== 'vault-page') ?? null,
   [effectiveRequested?.viewId, viewContributions.snapshot.plugins]);
   const stableActiveViewRef = useRef<PluginViewSnapshotSelection<ResolvedPluginView> | null>(null);
   const activeView = resolvePluginViewSnapshotSelection({

components/PluginVaultPages.test.tsx

@@ -0,0 +1,101 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { JSDOM } from 'jsdom';
+
+test('Vault navigation mounts a real content slot, yields to host dialogs, and withdraws stale pages', async () => {
+  const dom = new JSDOM('<!doctype html><html><body><div id="root"></div></body></html>', { pretendToBeVisual: true, url: 'http://localhost' });
+  const previous = new Map<string, PropertyDescriptor | undefined>();
+  for (const key of ['window', 'document', 'navigator', 'HTMLElement', 'Element', 'Node', 'MutationObserver', '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 Window] });
+  }
+  for (const [key, value] of Object.entries({ getComputedStyle: dom.window.getComputedStyle.bind(dom.window),
+    requestAnimationFrame: dom.window.requestAnimationFrame.bind(dom.window), cancelAnimationFrame: dom.window.cancelAnimationFrame.bind(dom.window), IS_REACT_ACT_ENVIRONMENT: true })) {
+    previous.set(key, Object.getOwnPropertyDescriptor(globalThis, key)); Object.defineProperty(globalThis, key, { configurable: true, writable: true, value });
+  }
+  dom.window.HTMLElement.prototype.getBoundingClientRect = () => ({ x: 200, y: 100, width: 640, height: 480, top: 100, left: 200, right: 840, bottom: 580, toJSON() {} });
+  const { default: React, act, useState } = await import('react');
+  const { createRoot } = await import('react-dom/client');
+  const { usePluginVaultPages } = await import('../application/state/usePluginVaultPages');
+  const { PluginVaultNavigation, PluginVaultPage } = await import('./plugins/PluginVaultPages');
+  const { activeTabStore } = await import('../application/state/activeTabStore');
+  const { requestOpenPluginView } = await import('../application/state/usePluginViewLifecycle');
+  const { I18nProvider } = await import('../application/i18n/I18nProvider');
+  const page = { id: 'com.example.page.main', title: 'Synthetic page', location: 'vault-page', entry: 'page.html', visible: true };
+  let snapshot = { locale: 'en', plugins: [{ id: 'com.example.page', version: '1.0.0', displayName: 'Synthetic plugin', commands: [], keybindings: [], menus: [], settings: [], views: [page] }] };
+  let changed: (() => void) | undefined;
+  const listeners = new Set<(event: NetcattyPluginViewClosedEvent) => void>();
+  const opens: NetcattyPluginViewOpenRequest[] = [], closes: string[] = [], visibility: boolean[] = [];
+  let defer: ((value: { instanceId: string }) => void) | undefined;
+  let deferOpen = false;
+  let delayLayout = false;
+  const rejectOldLayout: Array<(error: Error) => void> = [];
+  const layoutResult = () => delayLayout ? new Promise<void>((_resolve, reject) => { rejectOldLayout.push(reject); }) : Promise.resolve();
+  Object.assign(dom.window, { netcatty: {
+    async getPluginRuntimeStatus() { return { available: true }; },
+    async getPluginContributions() { return snapshot; },
+    onPluginContributionsChanged(fn: () => void) { changed = fn; return () => { changed = undefined; }; },
+    onPluginViewClosed(fn: (event: NetcattyPluginViewClosedEvent) => void) { listeners.add(fn); return () => { listeners.delete(fn); }; },
+    async openPluginView(payload: NetcattyPluginViewOpenRequest) { opens.push(payload); return deferOpen ? new Promise<{ instanceId: string }>((resolve) => { defer = resolve; }) : { instanceId: payload.instanceId! }; },
+    async closePluginView(id: string) { closes.push(id); }, async setPluginViewBounds() { await layoutResult(); },
+    async setPluginViewVisibility(_id: string, visible: boolean) { visibility.push(visible); await layoutResult(); },
+  } });
+  let selectSection!: (section: 'hosts' | `plugin-vault:${string}`) => void;
+  function Fixture() {
+    const [section, select] = useState<'hosts' | `plugin-vault:${string}`>('hosts'); selectSection = select;
+    const model = usePluginVaultPages({ locale: 'en', section, select });
+    return <><aside><button data-plugin-vault-fallback onClick={() => select('hosts')}>Hosts</button><PluginVaultNavigation model={model} collapsed={false} /></aside>
+      <main data-section="vault-main">{model.selected ? <PluginVaultPage key={model.selected.key} model={model} /> : <p>Built-in hosts</p>}</main></>;
+  }
+  const root = createRoot(document.getElementById('root')!);
+  const settle = () => new Promise((resolve) => setTimeout(resolve, 35));
+  const clickPage = async () => { await act(async () => { document.querySelector<HTMLButtonElement>('button[aria-label="Synthetic page — Synthetic plugin"]')!.click(); await settle(); }); };
+  try {
+    activeTabStore.setActiveTabId('vault');
+    await act(async () => { root.render(<I18nProvider locale="en"><Fixture /></I18nProvider>); await settle(); });
+    assert.equal(opens.length, 0, 'catalog enumeration does not activate the plugin');
+    await clickPage();
+    assert.ok(document.querySelector('[data-section="vault-main"] [data-plugin-view-slot="vault-page"]'));
+    assert.equal(opens.length, 1);
+    assert.deepEqual(opens[0].context, { 'netcatty.surface': 'vault-page' }, 'no Vault/session data accompanies navigation');
+    assert.equal(visibility.at(-1), true);
+    const dialog = document.createElement('div'); dialog.setAttribute('role', 'dialog'); dialog.setAttribute('aria-modal', 'true');
+    await act(async () => { document.body.append(dialog); await settle(); });
+    assert.equal(visibility.at(-1), false, 'native content yields to host security/settings dialogs');
+    await act(async () => { dialog.remove(); await settle(); });
+    assert.equal(visibility.at(-1), true);
+    await act(async () => { activeTabStore.setActiveTabId('terminal:synthetic'); assert.ok(closes.includes(opens[0].instanceId!)); await settle(); });
+    await act(async () => { activeTabStore.setActiveTabId('vault'); await settle(); });
+    assert.equal(opens.length, 2);
+    await act(async () => { snapshot = { ...snapshot, plugins: [] }; changed?.(); await settle(); });
+    await act(async () => { await settle(); });
+    assert.ok(closes.includes(opens[1].instanceId!));
+    assert.equal(document.querySelector('[data-plugin-vault-page]'), null);
+    assert.equal(document.activeElement?.textContent, 'Hosts');
+    await act(async () => { selectSection('plugin-vault:missing'); await settle(); });
+    assert.match(document.querySelector('main')!.textContent!, /Built-in hosts/);
+    await act(async () => { snapshot = { ...snapshot, plugins: [{ id: 'com.example.page', version: '1.0.0', displayName: 'Synthetic plugin', commands: [], keybindings: [], menus: [], settings: [], views: [page] }] }; changed?.(); await settle(); });
+    deferOpen = true;
+    await act(async () => { requestOpenPluginView({ viewId: page.id }); await settle(); });
+    assert.equal(opens.length, 3);
+    await act(async () => { selectSection('hosts'); await settle(); });
+    assert.ok(closes.includes(opens[2].instanceId!), 'cancel reserved instance before its open response');
+    await act(async () => { defer!({ instanceId: opens[2].instanceId! }); await settle(); });
+    assert.equal(document.querySelector('[data-plugin-vault-page]'), null, 'late open cannot restore withdrawn page');
+    assert.ok(closes.filter((id) => id === opens[2].instanceId).length >= 2, 'late native response is also closed');
+    deferOpen = false;
+    const second = { ...page, id: 'com.example.page.second', title: 'Second page' };
+    await act(async () => { snapshot = { ...snapshot, plugins: [{ ...snapshot.plugins[0], views: [page, second] }] }; changed?.(); await settle(); });
+    delayLayout = true;
+    await clickPage();
+    assert.ok(rejectOldLayout.length >= 2, 'old page has both bounds and visibility IPC in flight');
+    await act(async () => { selectSection('hosts'); await settle(); });
+    delayLayout = false;
+    await act(async () => { document.querySelector<HTMLButtonElement>('button[aria-label="Second page — Synthetic plugin"]')!.click(); await settle(); });
+    await act(async () => { for (const reject of rejectOldLayout) reject(new Error('old page layout failed')); await settle(); });
+    assert.equal(document.querySelector('[data-plugin-vault-page]')?.getAttribute('aria-label'), 'Second page', 'old bounds/visibility failures cannot withdraw the newly selected page');
+  } finally {
+    await act(async () => { root.unmount(); await settle(); }); dom.window.close();
+    for (const [key, descriptor] of previous) { if (descriptor) Object.defineProperty(globalThis, key, descriptor); else Reflect.deleteProperty(globalThis, key); }
+  }
+});

components/VaultView.tsx

@@ -161,6 +161,7 @@ import { VaultViewLayout } from "./vault/VaultViewLayout";
 import { useVaultHostCollections } from "./vault/useVaultHostCollections";
 import { useVaultImportHandlers } from "../application/state/useVaultImportHandlers";
 import { useVaultGroupDragHandlers } from "./vault/useVaultGroupDragHandlers";
+import { usePluginVaultPages } from "../application/state/usePluginVaultPages";
 
 const LazyProtocolSelectDialog = lazy(() => import("./ProtocolSelectDialog"));
 const LazyConnectionLogsManager = lazy(() => import("./ConnectionLogsManager"));
@@ -178,7 +179,8 @@ export type VaultSection =
   | "notes"
   | "port"
   | "knownhosts"
-  | "logs";
+  | "logs"
+  | `plugin-vault:${string}`;
 
 const haveSameHostOrderResult = (previous: Host[], next: Host[]) => {
   if (previous.length !== next.length) return false;
@@ -365,11 +367,12 @@ const VaultViewInner: React.FC<VaultViewProps> = ({
   onVaultFocusRequestHandled,
   terminalSettings,
 }) => {
-  const { t } = useI18n();
+  const { t, locale } = useI18n();
   const rootRef = useRef<HTMLDivElement>(null);
   const hostsRef = useRef(hosts);
   hostsRef.current = hosts;
   const [currentSection, setCurrentSection] = useState<VaultSection>("hosts");
+  const pluginVault = usePluginVaultPages({ locale, section: currentSection, select: setCurrentSection });
   const [search, setSearch] = useState("");
   const [selectedGroupPath, setSelectedGroupPath] = useState<string | null>(
     null,
@@ -1522,6 +1525,7 @@ const VaultViewInner: React.FC<VaultViewProps> = ({
           ContextMenuTrigger,
           Copy,
           currentSection,
+          pluginVault,
           customGroups,
           deleteGroupPath,
           deleteGroupPaths,

components/plugins/PluginVaultPages.tsx

@@ -0,0 +1,44 @@
+import { activeTabStore } from '../../application/state/activeTabStore';
+import { useI18n } from '../../application/i18n/I18nProvider';
+import { useEmbeddedPluginView } from '../../application/state/useEmbeddedPluginView';
+import type { usePluginVaultPages } from '../../application/state/usePluginVaultPages';
+import { PluginContributionIcon } from './PluginContributionIcon';
+import { Button } from '../ui/button';
+
+type VaultPages = ReturnType<typeof usePluginVaultPages>;
+const subscribeHidden = (hide: () => void) => activeTabStore.subscribeSync((id) => { if (id !== 'vault') hide(); });
+
+export function PluginVaultNavigation({ model, collapsed }: { model: VaultPages; collapsed: boolean }) {
+  const { t } = useI18n();
+  if (!model.pages.length) return null;
+  return <div role="group" aria-label={t('plugins.vault.extensions')} className="mt-3 space-y-1 border-t border-border/50 pt-3">
+    {!collapsed && <p className="px-2 text-xs text-muted-foreground">{t('plugins.vault.extensions')}</p>}
+    {model.pages.map((page) => <Button key={page.key} type="button"
+      variant={model.selected?.key === page.key ? 'secondary' : 'ghost'}
+      className={`w-full ${collapsed ? 'justify-center px-0' : 'justify-start gap-3'}`}
+      title={`${page.title} — ${page.pluginName}`}
+      aria-label={`${page.title} — ${page.pluginName}`}
+      aria-current={model.selected?.key === page.key ? 'page' : undefined}
+      onClick={() => model.select(page.key)}>
+      <PluginContributionIcon pluginId={page.pluginId} icon={page.icon} className="shrink-0" />
+      {!collapsed && <span className="truncate">{page.title}</span>}
+    </Button>)}
+  </div>;
+}
+
+export function PluginVaultPage({ model }: { model: VaultPages }) {
+  const { t } = useI18n();
+  const page = model.selected!;
+  const { mountRef, loading } = useEmbeddedPluginView({ viewId: page.viewId, version: page.version, slot: 'vault-page',
+    active: model.active, context: model.context, adapter: model.contributions, subscribeHidden, unavailable: model.fallback });
+  return <section className="flex min-h-0 flex-1 flex-col" aria-label={page.title} data-plugin-vault-page={page.key}>
+    <header className="app-no-drag flex h-12 shrink-0 items-center justify-between gap-3 border-b border-border px-4">
+      <div className="min-w-0"><h2 className="truncate text-sm font-medium">{page.title}</h2>
+        <p className="truncate text-xs text-muted-foreground">{page.pluginName} · {page.version}</p></div>
+      <Button variant="ghost" onClick={model.fallback}>{t('plugins.vault.back')}</Button>
+    </header>
+    <div ref={mountRef} className="relative min-h-0 flex-1 overflow-hidden" data-plugin-view-slot="vault-page">
+      {loading && <p role="status" className="p-4 text-sm text-muted-foreground">{t('plugins.vault.loading')}</p>}
+    </div>
+  </section>;
+}

components/vault/VaultViewLayout.tsx

@@ -29,6 +29,7 @@ import { LazyLoadBoundary } from "../ui/lazy-load-boundary";
 import { toast } from "../ui/toast";
 import { AppWordmark } from "../AppWordmark";
 import { openHostBrowser } from "../../application/hostBrowser";
+import { PluginVaultNavigation, PluginVaultPage } from '../plugins/PluginVaultPages';
 
 type VaultViewLayoutContext = Record<string, any>;
 
@@ -156,6 +157,7 @@ export function VaultViewLayout({ ctx }: { ctx: VaultViewLayoutContext }) {
     ContextMenuTrigger,
     Copy,
     currentSection,
+    pluginVault,
     customGroups,
     deleteGroupPaths,
     deleteGroupWithHosts,
@@ -595,12 +597,13 @@ export function VaultViewLayout({ ctx }: { ctx: VaultViewLayoutContext }) {
           </div>
 
           <div
-            className={cn("space-y-1", sidebarCollapsed ? "px-1.5" : "px-2.5")}
+            className={cn("min-h-0 flex-1 overflow-y-auto space-y-1", sidebarCollapsed ? "px-1.5" : "px-2.5")}
           >
             <Tooltip>
               <TooltipTrigger asChild>
                 <RippleButton
                   variant={currentSection === "hosts" ? "secondary" : "ghost"}
+                  data-plugin-vault-fallback
                   className={cn(
                     "w-full h-10",
                     sidebarCollapsed
@@ -805,11 +808,12 @@ export function VaultViewLayout({ ctx }: { ctx: VaultViewLayoutContext }) {
                 </TooltipContent>
               )}
             </Tooltip>
+            {pluginVault && <PluginVaultNavigation model={pluginVault} collapsed={sidebarCollapsed} />}
           </div>
 
           <div
             className={cn(
-              "mt-auto pb-4 space-y-2",
+              "mt-auto shrink-0 pb-4 space-y-2",
               sidebarCollapsed ? "px-1.5" : "px-2.5",
             )}
           >
@@ -864,6 +868,7 @@ export function VaultViewLayout({ ctx }: { ctx: VaultViewLayoutContext }) {
             className="flex-1 min-w-0 flex flex-col min-h-0 relative"
             data-section="vault-main"
           >
+            {pluginVault?.selected && <PluginVaultPage key={pluginVault.selected.key} model={pluginVault} />}
             <VaultPageHeader
               className={cn(!isHostsSectionActive && "hidden")}
               dataSection="vault-hosts-header"

docs/plugin-platform/capability-coverage.md

@@ -17,7 +17,7 @@ mean complete. Existing APIs remain available.
 | Terminal providers | Decorations, links, completion, snapshots through provider requests | Session change delivery follows prior provider request and non-once grant | Preserve providers. Standalone selected-session watch planned | Hostnames, session state, endpoint identity | Host-selected session, runtime identity | Session-close and revoke cleanup, bounded event rate | Existing provider tests. Ordinary views cannot independently subscribe today |
 | Current context and host picker | Host context keys are boolean state | `vault.metadata` enumeration is not generic SDK | Selected host/session DTO from an explicit whitelist | Labels and endpoint metadata are sensitive | Host-owned user-action context, selected host/session | TTL, runtime and session invalidation, redacted audit | Planned. Never reuse agent `sanitizeHostForAgent` as plugin DTO |
 | Terminal selection and input draft | Provider-supplied snapshots, completion suggestions | No explicit selection-share or draft API | User shares selection, plugin proposes a visible editable draft | Terminal plaintext, accidental execution | Host action token plus exact live session/endpoint | Single-use token, size cap, no plaintext audit, active identity before commit | Planned. Reject Enter/control characters for draft insertion. No full history or direct shell |
-| Native interactions and clipboard | Native permission dialogs; new browser SDK host choice/input and explicit copy/share workflow | Progress/toast remain unimplemented | Host-owned prompts, two-phase clipboard snapshot/share, exact copy preview | Clipboard and input may contain secrets; UI discloses granted network capability; prompt spam | `ui.interact`, clipboard direction, host-signed window/runtime/version/phase/TTL action | Admission before permission prompt, byte/rate/concurrency limits, lock/blur/close/revoke cleanup, active guard, content-free audit | [Host interaction slice](./host-interactions.md) implemented and synthetic-tested; native acceptance/review/CI pending. Progress/toast still planned. No background reads or trusted plugin `userGesture` boolean |
+| Native interactions and clipboard | Native permission dialogs; new browser SDK host choice/input and explicit copy/share workflow | Progress/toast remain unimplemented | Host-owned prompts, two-phase clipboard snapshot/share, exact copy preview | Clipboard and input may contain secrets; UI discloses granted network capability; prompt spam | `ui.interact`, clipboard direction, host-signed window/runtime/version/phase/TTL action | Admission before permission prompt, byte/rate/concurrency limits, lock/blur/close/revoke cleanup, active guard, content-free audit | [Host interaction slice](./host-interactions.md) implemented and synthetic-tested. d4ca123 exact test/packaging CI and parent independent delta review passed; parent native rerun pending after the permission-modal focus fix. Progress/toast still planned. No background reads or trusted plugin `userGesture` boolean |
 | Local filesystem | Read file, stat, overwrite existing regular file | Directory listing lacks same-handle native adapter | Keep current boundary, evaluate file picker handles | Arbitrary local file content and writes | Canonical exact path or selected file handle | Inode checks, no symlink alias, bounded bytes, active runtime | Existing filesystem tests. Directory enumeration and new arbitrary-path creation deferred until portable safe native adapter exists |
 | SFTP and remote files | No generic plugin API | `sftp.read` and `sftp.write` enumerated only | Host-selected session/path/mode/TTL handles, read and explicit save/upload | Remote secrets and destructive overwrite | Live endpoint identity, exact path, read/write split | Cancel streams, byte quota, overwrite confirmation, close/revoke cleanup | Batch 2 planned. Never forward arbitrary MCP catalog or session ID alone |
 | Editor and Notes | No plugin document API | No versioned snapshot or edit preview | Explicit snapshot and versioned proposed edit | Document secrets, lost updates, executable files | Selected document plus revision and action token | Version conflict check, preview, bounded bytes, revocation | Planned evaluation after shared action context. No unattended edits |
@@ -32,7 +32,7 @@ mean complete. Existing APIs remain available.
 | AI, MCP, automation | Host agent catalog and harness exist separately | No generic plugin AI or tool forwarding | Selection-to-proposal workflow through the same controlled primitives | Content disclosure, account authority and model cost | Explicit content sharing plus service origin/budget | No inherited history, tools, account, or hidden cron | Controlled workflow planned. Generic host AI and visible schedules deferred to distinct product decision |
 | Known hosts, app lock and global security | Host security management UI | No plugin management API | Future allowlisted security-page navigation | Host-key trust, unlock, keys and security policy affect all sessions | Host navigation action only | No mutation or sensitive DTO | Security policy mutation, private-key reads, auto-trust and unlocking deferred indefinitely |
 | Plugin blob/cache | Local KV exists | No exclusive blob cache | Evaluate bounded plugin-owned cache when a real workflow needs it | Disk growth and lifecycle ambiguity | Plugin namespace, no arbitrary path | Size quota, eviction and uninstall policy required | Deferred until a concrete larger-than-KV workflow establishes value and retention policy |
-| Vault and terminal navigation | `tab` mounts a sandbox page through TopTabs/QuickSwitcher; aside/panel are overlays | No Vault subpage registry or terminal side-panel plugin tool. `settings` is a detail entry, not a new settings category | Accepted independent slice: host-owned namespaced Vault pages in an Extensions group, mounted in the Vault content area through existing ViewHost; then terminal pane/split pages for the selected session | Navigation cannot disclose session contents or replace built-in/security navigation | Declared page contribution plus host selection. Content reads have independent permissions | Host order/when/focus, cancellation of late open, view cleanup on hide/update/disable/uninstall, safe invalid-link fallback | Planned after host interaction/selected-context workflow. A button that merely opens a top tab does not satisfy Vault-page acceptance. No arbitrary router/DOM API |
+| Vault and terminal navigation | `tab` mounts a sandbox page through TopTabs/QuickSwitcher; aside/panel are overlays | No Vault subpage registry or terminal side-panel plugin tool. `settings` is a detail entry, not a new settings category | Accepted independent slice: host-owned namespaced Vault pages in an Extensions group, mounted in the Vault content area through existing ViewHost; then terminal pane/split pages for the selected session | Navigation cannot disclose session contents or replace built-in/security navigation | Declared page contribution plus host selection. Content reads have independent permissions | Host order/when/focus, cancellation of late open, view cleanup on hide/update/disable/uninstall, safe invalid-link fallback | [Vault page slice](./vault-pages.md) implemented and synthetic-tested: actual Vault content slot, private Scratchpad, catalog withdrawal, host occlusion, reserved-open cancellation, owner/crash/lock cleanup. Exact CI/independent/native acceptance pending. Terminal pane/split pages remain the next separate stage. No arbitrary router/DOM API |
 | Distribution and runtimes | Browser-only public catalog, immutable packages, advanced developer gate | Signing/trust and release remain separate phase | Retain existing boundary | Package execution and publisher trust | Pinned catalog selection, hash, engine/features | Existing install transaction, quarantine and cleanup | No merge/release. Do not extend to arbitrary Node, IPC, shell, or global capabilities |
 
 ## Delivery order and stopping rule
@@ -83,3 +83,18 @@ Baseline code references: `electron/plugins/hostService.cjs`,
 implementations under `electron/capabilities/catalog/` are reference material,
 not plugin authority. `infrastructure/ai/vaultAgentBridgeClient.ts` is not a
 plugin DTO sanitizer.
+
+## Navigation slice checkpoint
+
+The Vault stage adds `views.vault-pages`, the `vault-page` location, and the
+existing `views` permission. It grants no Vault/session data. The ordinary
+browser Scratchpad example uses only its own bounded view-state API and
+explicit user input. It is not a Notes API or automatic sync feature.
+
+The independent integration base includes #3956 UI polish and #3960 d4ca fixes;
+frozen evidence heads and prior PR bases are unchanged. Related UI changes in
+this stage are limited to VaultView/VaultViewLayout, new independent plugin
+components/hooks, and localized strings. PluginMarketplace/PluginPackageManager
+layouts are not rewritten. Native acceptance belongs to the parent with a new
+fixture-specific own-views approval. Sidebar, ThemePack, selected context and
+SFTP remain unfinished; this checkpoint is not overall completion.

docs/plugin-platform/vault-pages.md

@@ -0,0 +1,80 @@
+# Vault extension pages
+
+`views.vault-pages` adds the `vault-page` view location. A package must require
+the feature and declare the existing `views` permission. Hosts without the
+feature reject the package deterministically. Existing view locations and API
+versions keep their behavior; there is no public plugin router or new Vault
+read/write permission.
+
+## User workflow
+
+Visible, enabled contributions appear in Vault's **Extensions** group. The
+host generates a namespaced route from the declared view ID, orders by declared
+order and ID, localizes the label, and resolves the declared icon through the
+existing safe icon pipeline. Built-in navigation and security entry points
+remain host-owned. Collapsed navigation retains source-labelled accessible
+buttons.
+
+Selecting a page mounts its existing sandbox WebContentsView in the Vault main
+content area. It does not create a top tab, use an aside overlay, open a
+connection, or share host/session/Vault records. The trusted host context
+contains only `netcatty.surface: vault-page`. The manager's existing Open action
+can select the same page through an internal host event; this is not exposed
+as a generic SDK navigation capability.
+
+The `vault-scratchpad` browser example lets the user type synthetic text, save
+it in the plugin's own view state, return to Hosts, reopen, and clear it. It
+does not create a Vault Note or enable automatic cloud sync. The fixture asks
+for only `views`; granting it does not approve another plugin or data access.
+
+## Ownership and lifecycle
+
+The host owns the route and validates the selected contribution against the
+current visible catalog. Missing IDs, disable/uninstall/update, a false `when`,
+failed activation or a host close return to Hosts. Focus restoration checks
+the current section and active tab so an old fallback cannot steal focus after
+a newer selection. Catalog listing does not activate a plugin.
+
+The embedded host reuses PluginViewHost, its ephemeral session, CSP, no-Node
+preload, protocol validation, own-command checks, and bounded own view state.
+No DOM or Electron object enters the SDK. A window-route-and-slot scope separates
+this page's state from other view placements; actual BrowserWindow ownership is
+validated separately and does not rely on that state key. This initial embedded slice
+closes on navigation away even if `retainContextWhenHidden` is declared.
+
+Each opening reserves an instance ID owned by its actual BrowserWindow before
+asynchronous activation. Close can cancel that reservation before native
+construction. Owner closure, shutdown and renderer cleanup prevent a late open
+from attaching; late responses are also closed by the renderer lifecycle
+controller. Current plugin version/runtime and `when` are checked before
+attachment and on subsequent contribution changes. Existing owner checks apply
+to bounds, visibility, close and view-state IPC.
+
+Host reload/renderer exit and a view renderer crash close the associated native
+page. Plain Escape in a Vault page is handled by the host and returns to Hosts;
+it does not dispatch a plugin command or expose a general navigation API.
+
+Native child views sit above React portals. A Vault page starts hidden; the
+trusted renderer reveals it only after checking the mount and host dialogs,
+menus, popovers, overlay panels and lock surfaces. Overlapping host surfaces
+hide the page. App Lock additionally closes all hosted plugin views and
+cancels pending opens in the main process; showing a view while locked fails.
+
+The shared manifest bound remains 128 views per package. Only one Vault page is
+mounted per owner; listing and routing do not create a background view queue.
+View-state JSON size limits and existing runtime/permission quotas remain in
+force. No page text or state is added to audit logs by this adapter.
+
+## Validation status
+
+Source tests cover normal catalog selection, the actual embedded content slot,
+host-modal occlusion, synchronous tab-away cleanup, withdrawn and invalid
+routes, internal host selection, delayed open cancellation, feature/permission
+admission, host ownership, `when` withdrawal and App Lock. Production build,
+aggregate host tests and precise-SHA CI are reported on the accompanying Draft
+PR. Parent native acceptance must use the packed browser example through
+normal Settings and record its exact source SHA/package hash. Unit tests do
+not substitute for that native acceptance.
+
+Terminal sidebar pages and selected-session DTOs remain separate stages. This
+page location does not make those capabilities available.

electron/plugins/generated/plugin-contract.schema.json

@@ -1293,9 +1293,13 @@
         "panel",
         "tab",
         "modal",
-        "settings"
+        "settings",
+        "vault-page"
       ]
     },
+    "VaultPagesFeature": {
+      "const": "views.vault-pages"
+    },
     "ViewContribution": {
       "type": "object",
       "required": [

electron/plugins/hostService.cjs

@@ -2,6 +2,7 @@
 
 const path = require("node:path");
 const NETWORK_CREDENTIAL_LEASE_FEATURE = require("./generated/plugin-contract.schema.json").$defs.NetworkCredentialLeaseFeature.const;
+const VAULT_PAGES_FEATURE = require("./generated/plugin-contract.schema.json").$defs.VaultPagesFeature.const;
 const INTERACTIVE_COMMAND_FEATURE = require("./generated/plugin-contract.schema.json").$defs.InteractiveCommandFeature.const;
 
 const { assertBrowserOnlyPlugin } = require("../../domain/pluginRuntimePolicy.cjs");
@@ -96,7 +97,7 @@ function createPluginHostService(options) {
       database,
       netcattyVersion: options.app.getVersion(),
       apiVersion: PLUGIN_API_VERSION,
-      supportedFeatures: [...new Set(["metadata.brand-icon", NETWORK_CREDENTIAL_LEASE_FEATURE, HOST_INTERACTION_FEATURE, INTERACTIVE_COMMAND_FEATURE, ...(options.supportedFeatures ?? [])])],
+      supportedFeatures: [...new Set(["metadata.brand-icon", NETWORK_CREDENTIAL_LEASE_FEATURE, HOST_INTERACTION_FEATURE, VAULT_PAGES_FEATURE, INTERACTIVE_COMMAND_FEATURE, ...(options.supportedFeatures ?? [])])],
     });
     const contributionIconService = new PluginContributionIconService({
       database,
@@ -236,7 +237,7 @@ function createPluginHostService(options) {
       paths,
       netcattyVersion: options.app.getVersion(),
       apiVersion: PLUGIN_API_VERSION,
-      supportedFeatures: [...new Set(["metadata.brand-icon", NETWORK_CREDENTIAL_LEASE_FEATURE, HOST_INTERACTION_FEATURE, INTERACTIVE_COMMAND_FEATURE, ...(options.supportedFeatures ?? [])])],
+      supportedFeatures: [...new Set(["metadata.brand-icon", NETWORK_CREDENTIAL_LEASE_FEATURE, HOST_INTERACTION_FEATURE, VAULT_PAGES_FEATURE, INTERACTIVE_COMMAND_FEATURE, ...(options.supportedFeatures ?? [])])],
       runtimeDirectory,
       appRoot,
       rpcRegistry,
@@ -364,6 +365,8 @@ function createPluginHostService(options) {
           packageStore,
           database,
           contributionService,
+          isLocked: options.isAppLocked,
+          subscribeLock: options.subscribeAppLock,
         })
       : null;
     const manager = new PluginManager({

electron/plugins/pluginViewHost.cjs

@@ -36,10 +36,19 @@ class PluginViewHost {
     this.contributionService = options.contributionService;
     this.preloadPath = options.preloadPath ?? path.join(__dirname, "runtime", "viewPreload.cjs");
     this.instances = new Map();
+    this.opening = new Map();
+    this.closed = false;
+    this.isLocked = options.isLocked ?? (() => false);
+    this.subscriptions = [];
+    const unsubscribeLock = options.subscribeLock?.((state) => {
+      if (!state.locked) return;
+      for (const opening of this.opening.values()) opening.cancelled = true;
+      for (const instanceId of [...this.instances.keys()]) void this.close(instanceId, undefined, "app-locked");
+    });
+    this.subscriptions.push({ dispose: () => unsubscribeLock?.() });
     this.byWebContentsId = new Map();
     this.closeListeners = new Set();
     this.environment = { locale: "en", theme: "system", reducedMotion: false, highContrast: false };
-    this.subscriptions = [];
     this.#registerIpc();
     this.subscriptions.push(this.contributionService.onDidPostViewMessage((event) => {
       for (const instance of this.instances.values()) {
@@ -49,10 +58,14 @@ class PluginViewHost {
       }
     }));
     this.subscriptions.push(this.contributionService.onDidChange?.((event) => {
-      if (!["plugin-disabled", "runtime-stopped", "runtime-error", "runtime-quarantined"].includes(event.reason)
-        || !event.pluginId) return;
       for (const instance of [...this.instances.values()]) {
-        if (instance.pluginId === event.pluginId) void this.close(instance.instanceId, undefined, event.reason);
+        if (["plugin-disabled", "runtime-stopped", "runtime-error", "runtime-quarantined"].includes(event.reason)
+          && instance.pluginId === event.pluginId) {
+          void this.close(instance.instanceId, undefined, event.reason);
+        } else if (instance.location === "vault-page") {
+          try { this.contributionService.assertViewActivationCurrent(instance.activation, { context: instance.context }); }
+          catch { void this.close(instance.instanceId, undefined, "contribution-unavailable"); }
+        }
       }
     }));
   }
@@ -115,10 +128,45 @@ class PluginViewHost {
 
   async open(payload, sender) {
     if (!payload || typeof payload !== "object") throw new TypeError("Plugin view request is invalid");
+    const owner = this.electron.BrowserWindow.fromWebContents(sender);
+    if (this.closed || this.isLocked() || !owner || owner.isDestroyed()) throw new Error("Plugin view owner is unavailable");
+    const instanceId = typeof payload.instanceId === "string" && payload.instanceId.length <= 128
+      ? payload.instanceId : randomUUID();
+    if (this.instances.has(instanceId) || this.opening.has(instanceId)) throw new Error(`Plugin view already exists: ${instanceId}`);
+    const opening = { owner, cancelled: false };
+    const cancel = () => { opening.cancelled = true; };
+    const rendererGone = () => { void this.close(instanceId, undefined, "owner-renderer-gone"); };
+    const navigate = (details, _url, isInPlace, isMainFrame) => {
+      if ((details?.isMainFrame ?? isMainFrame) !== false && (details?.isSameDocument ?? isInPlace) !== true) rendererGone();
+    };
+    const cleanupOwner = () => {
+      sender.removeListener?.("render-process-gone", rendererGone);
+      sender.removeListener?.("did-start-navigation", navigate);
+    };
+    this.opening.set(instanceId, opening);
+    owner.once?.("closed", cancel);
+    sender.on?.("render-process-gone", rendererGone);
+    sender.on?.("did-start-navigation", navigate);
+    try { return await this.#open({ ...payload, instanceId }, sender, opening); }
+    finally {
+      owner.removeListener?.("closed", cancel);
+      const instance = this.instances.get(instanceId);
+      if (instance) instance.cleanupOwner = cleanupOwner;
+      else cleanupOwner();
+      if (this.opening.get(instanceId) === opening) this.opening.delete(instanceId);
+    }
+  }
+
+  #assertOpening(opening) {
+    if (this.closed || this.isLocked() || opening.cancelled || opening.owner.isDestroyed()) throw new Error("Plugin view opening was cancelled");
+  }
+
+  async #open(payload, sender, opening) {
     const { plugin, view, identity } = await this.contributionService.activateView(
       payload.viewId,
       { context: payload.context },
     );
+    this.#assertOpening(opening);
     const activation = Object.freeze({
       pluginId: plugin.id,
       pluginVersion: plugin.activeVersion,
@@ -135,6 +183,7 @@ class PluginViewHost {
       : randomUUID();
     if (this.instances.has(instanceId)) throw new Error(`Plugin view already exists: ${instanceId}`);
     const packageRoot = await this.packageStore.preparePackageRoot(plugin);
+    this.#assertOpening(opening);
     this.contributionService.assertViewActivationCurrent(activation, { context: payload.context });
     const partition = `netcatty-plugin-view-${randomUUID()}`;
     const pluginSession = this.electron.session.fromPartition(partition, { cache: false });
@@ -183,12 +232,22 @@ class PluginViewHost {
         if (url !== registration.url) event.preventDefault();
       });
       contents.on("will-attach-webview", (event) => event.preventDefault());
+      contents.once("render-process-gone", () => { void this.close(instanceId, undefined, "view-renderer-gone"); });
+      if (view.location === "vault-page") contents.on("before-input-event", (event, input) => {
+        if (input.type === "keyDown" && input.key === "Escape" && !input.control && !input.meta && !input.alt && !input.shift) {
+          event.preventDefault();
+          void this.close(instanceId, undefined, "host-escape");
+        }
+      });
       const ownerClosed = () => { void this.close(instanceId, undefined, "owner-closed"); };
       const instance = {
         instanceId,
         pluginId: plugin.id,
         viewId: view.id,
         scopeId,
+        location: view.location,
+        activation,
+        context: structuredClone(payload.context ?? {}),
         owner,
         ownerClosed,
         view: contentsView,
@@ -197,6 +256,7 @@ class PluginViewHost {
         sessionRegistration,
         state: "opening",
         attached: false,
+        visible: view.location !== "vault-page",
       };
       this.instances.set(instanceId, instance);
       this.byWebContentsId.set(contents.id, instance);
@@ -208,6 +268,10 @@ class PluginViewHost {
         || owner.isDestroyed() || contents.isDestroyed()) {
         throw new Error("Plugin view ownership changed while opening");
       }
+      this.#assertOpening(opening);
+      // Embedded pages start hidden until the trusted renderer checks host
+      // dialogs/lock/popovers. A late open must never cover a security surface.
+      if (view.location === "vault-page") contentsView.setVisible(false);
       owner.contentView.addChildView(contentsView);
       instance.attached = true;
       contentsView.setBounds(normalizeBounds(payload.bounds));
@@ -232,7 +296,11 @@ class PluginViewHost {
   setVisible(instanceId, visible, sender) {
     if (typeof visible !== "boolean") throw new TypeError("Plugin view visibility must be a boolean");
     const instance = this.#ownedInstance(instanceId, sender);
+    if (visible && this.isLocked()) throw new Error("Plugin view owner is unavailable");
+    const rising = visible && !instance.visible;
+    instance.visible = visible;
     instance.view.setVisible(visible);
+    if (rising && instance.location === "vault-page" && instance.owner.isFocused?.()) instance.contents.focus?.();
   }
 
   async postMessage(instanceId, message, sender) {
@@ -250,11 +318,17 @@ class PluginViewHost {
   }
 
   async close(instanceId, sender, reason = sender ? "renderer-requested" : "host-requested") {
+    const opening = this.opening.get(instanceId);
+    if (opening) {
+      if (sender && this.electron.BrowserWindow.fromWebContents(sender) !== opening.owner) throw new Error("Untrusted plugin view owner");
+      opening.cancelled = true;
+    }
     const instance = this.instances.get(instanceId);
     if (!instance) return;
     if (sender) this.#ownedInstance(instanceId, sender);
     this.instances.delete(instanceId);
     this.byWebContentsId.delete(instance.contents.id);
+    try { instance.cleanupOwner?.(); } catch {}
     try { instance.owner.removeListener?.("closed", instance.ownerClosed); } catch {}
     if (instance.attached) {
       try { instance.owner.contentView.removeChildView(instance.view); } catch {}
@@ -279,6 +353,8 @@ class PluginViewHost {
   }
 
   async shutdown() {
+    this.closed = true;
+    for (const opening of this.opening.values()) opening.cancelled = true;
     await Promise.all([...this.instances.keys()].map((instanceId) => this.close(instanceId)));
     for (const subscription of this.subscriptions.splice(0)) subscription?.dispose?.();
     this.closeListeners.clear();

electron/plugins/pluginViewHost.test.cjs

@@ -87,9 +87,10 @@ function fixture(options = {}) {
     onDidPostViewMessage(listener) { viewListener = listener; return { dispose() {} }; },
     onDidChange(listener) { changeListener = listener; return { dispose() {} }; },
     async activateView() {
+      await options.activateView?.();
       return {
         plugin: { id: "com.example.view", activeVersion: "1.0.0" },
-        view: { id: "com.example.view.panel", entry: "view.html", location: "aside" },
+        view: { id: "com.example.view.panel", entry: "view.html", location: options.location ?? "aside" },
         identity: { runtimeId: "runtime-view-1", pluginVersion: "1.0.0" },
       };
     },
@@ -121,6 +122,8 @@ function fixture(options = {}) {
       setViewState(pluginId, viewId, scopeId, value) { state.set(`${pluginId}:${viewId}:${scopeId}`, value); },
     },
     contributionService,
+    isLocked: options.isLocked,
+    subscribeLock: options.subscribeLock,
     preloadPath: "/runtime/viewPreload.cjs",
   });
   function createOwner() {
@@ -131,7 +134,7 @@ function fixture(options = {}) {
       addChildView(view) { owner.children.push(view); },
       removeChildView(view) { owner.children = owner.children.filter((entry) => entry !== view); },
     };
-    const sender = {};
+    const sender = new EventEmitter();
     senderOwners.set(sender, owner);
     return { owner, sender };
   }
@@ -341,3 +344,114 @@ test("view cleanup failures cannot suppress owner removal or the renderer close
     reason: "renderer-requested",
   }]);
 });
+
+test("Vault pages start hidden and are withdrawn when their current contribution is no longer available", async () => {
+  const value = fixture({ location: "vault-page" });
+  const { owner, sender } = value.createOwner();
+  const result = await value.host.open({ viewId: "com.example.view.panel", scopeId: "window-1:vault-page" }, sender);
+  assert.equal(owner.children.length, 1);
+  assert.equal(value.views[0].visible, false, "host modal checks precede native visibility");
+  value.host.setVisible(result.instanceId, true, sender);
+  assert.equal(value.views[0].visible, true);
+  value.setActivationCurrent(false);
+  value.changeListener()({ reason: "context-key-changed" });
+  assert.equal(owner.children.length, 0);
+  assert.equal(value.views[0].webContents.destroyed, true);
+  await value.host.shutdown();
+});
+
+test("closing a reserved owner instance cancels activation before any native page is constructed", async () => {
+  let release;
+  const gate = new Promise((resolve) => { release = resolve; });
+  const value = fixture({ location: "vault-page", activateView: () => gate });
+  const { owner, sender } = value.createOwner();
+  const other = value.createOwner();
+  const opening = value.host.open({ viewId: "com.example.view.panel", scopeId: "window-1:vault-page", instanceId: "reserved-page" }, sender);
+  await assert.rejects(value.host.close("reserved-page", other.sender), /Untrusted/);
+  await value.host.close("reserved-page", sender);
+  release();
+  await assert.rejects(opening, /cancelled/);
+  assert.equal(value.views.length, 0);
+  assert.equal(owner.children.length, 0);
+  assert.equal(value.host.opening.size, 0);
+  await value.host.shutdown();
+});
+
+test("app lock closes attached pages and cancels pending opens, with subscription cleanup", async () => {
+  let listener, locked = false, disposed = 0;
+  const value = fixture({ location: "vault-page", isLocked: () => locked,
+    subscribeLock(fn) { listener = fn; return () => { disposed++; }; } });
+  const { owner, sender } = value.createOwner();
+  const result = await value.host.open({ viewId: "com.example.view.panel", scopeId: "window-1:vault-page" }, sender);
+  locked = true; listener({ locked: true });
+  assert.equal(owner.children.length, 0);
+  assert.equal(value.views[0].webContents.destroyed, true);
+  await assert.rejects(value.host.open({ viewId: "com.example.view.panel", scopeId: "window-1:vault-page" }, sender), /unavailable/);
+  assert.throws(() => value.host.setVisible(result.instanceId, true, sender));
+  await value.host.shutdown();
+  assert.equal(disposed, 1);
+});
+
+test("browser Scratchpad saves, reopens and clears only its own view state through the real host IPC", async () => {
+  const { readFile } = require("node:fs/promises");
+  const path = require("node:path");
+  const { JSDOM } = require("jsdom");
+  const { VIEW_CHANNELS } = require("./pluginViewHost.cjs");
+  const html = await readFile(path.join(__dirname, "../../examples/plugins/vault-scratchpad/page.html"), "utf8");
+  const script = await readFile(path.join(__dirname, "../../examples/plugins/vault-scratchpad/page.js"), "utf8");
+  const value = fixture({ location: "vault-page" });
+  const { sender } = value.createOwner();
+  async function open(scopeId) {
+    const result = await value.host.open({ viewId: "com.example.view.panel", scopeId }, sender);
+    const contents = value.host.instances.get(result.instanceId).contents;
+    const dom = new JSDOM(html, { runScripts: "outside-only" });
+    dom.window.netcattyView = {
+      getState: async () => value.ipcHandlers.get(VIEW_CHANNELS.getState)({ sender: contents }),
+      setState: async (state) => value.ipcHandlers.get(VIEW_CHANNELS.setState)({ sender: contents }, structuredClone(state)),
+    };
+    dom.window.eval(script);
+    await new Promise((resolve) => setImmediate(resolve));
+    return { dom, document: dom.window.document, id: result.instanceId, contents };
+  }
+  const first = await open("window-1:vault-page");
+  first.document.getElementById("draft").value = "synthetic private draft";
+  first.document.getElementById("save").click();
+  await new Promise((resolve) => setImmediate(resolve));
+  assert.match(first.document.getElementById("status").textContent, /saved/);
+  await value.host.close(first.id, sender); first.dom.window.close();
+  const separate = await open("window-2:vault-page");
+  assert.equal(separate.document.getElementById("draft").value, "", "a different host-owned state scope does not inherit this draft");
+  const reopened = await open("window-1:vault-page");
+  assert.equal(reopened.document.getElementById("draft").value, "synthetic private draft");
+  reopened.document.getElementById("clear").click();
+  await new Promise((resolve) => setImmediate(resolve));
+  assert.equal(reopened.document.getElementById("draft").value, "");
+  const cleared = await open("window-1:vault-page");
+  assert.equal(cleared.document.getElementById("draft").value, "");
+  await value.host.shutdown();
+  assert.throws(() => value.ipcHandlers.get(VIEW_CHANNELS.getState)({ sender: reopened.contents }), /Untrusted/);
+  for (const panel of [separate, reopened, cleared]) panel.dom.window.close();
+});
+
+test("host reload, host/view renderer exit, and host Escape close embedded pages", async () => {
+  for (const action of ["reload", "host-exit", "view-exit", "escape"]) {
+    const value = fixture({ location: "vault-page" });
+    const { sender, owner } = value.createOwner();
+    const opened = await value.host.open({ viewId: "com.example.view.panel", scopeId: "window-1:vault-page" }, sender);
+    const contents = value.views[0].webContents;
+    sender.emit("did-start-navigation", { isMainFrame: true, isSameDocument: true });
+    assert.equal(owner.children.length, 1);
+    if (action === "reload") sender.emit("did-start-navigation", { isMainFrame: true, isSameDocument: false });
+    if (action === "host-exit") sender.emit("render-process-gone");
+    if (action === "view-exit") contents.emit("render-process-gone");
+    if (action === "escape") {
+      let prevented = false;
+      contents.emit("before-input-event", { preventDefault() { prevented = true; } }, { type: "keyDown", key: "Escape" });
+      assert.equal(prevented, true);
+    }
+    assert.equal(owner.children.length, 0, action);
+    assert.equal(value.host.instances.has(opened.instanceId), false, action);
+    assert.equal(sender.listenerCount("render-process-gone"), 0, action);
+    await value.host.shutdown();
+  }
+});

examples/plugins/vault-scratchpad/README.md

@@ -0,0 +1,27 @@
+# Vault Scratchpad
+
+Browser-only example of an actual Vault extension page. It needs only `views`
+and the required `views.vault-pages` feature. No host/session/Vault data,
+clipboard, network, filesystem, credentials or shell permission is requested.
+Text explicitly typed here is stored in this plugin's own bounded view state;
+it is not a Netcatty Note and is not automatically cloud-synced.
+
+```sh
+node packages/plugin-cli/dist/cli.js pack examples/plugins/vault-scratchpad --out /tmp/vault-scratchpad.ncpkg
+```
+
+Import disabled through normal Settings, inspect and enable it. Under Vault's
+**Extensions** group choose **Scratchpad**. The sandbox must fill Vault's main
+content area, retaining the built-in sidebar and top tabs. Opening its detail
+entry must navigate to this same Vault page, without creating a top plugin tab.
+
+For native QA, a separate explicit approval for this fixture's own `views`
+permission is required; earlier fixtures' grants do not cover this ID. With
+synthetic text, save, return to Hosts and reopen; verify the draft. Clear and
+reopen to verify deletion. Cancel the first permission prompt to verify that no
+page attaches. Switch away during opening, then disable/revoke and verify the
+page/entry disappear. Closing or withdrawing a page returns to Hosts. A host
+modal or overlapping menu must hide the native view while it is present.
+
+This source example is not independent/native acceptance evidence. Parent QA
+records the precise tested commit and package hash separately.

examples/plugins/vault-scratchpad/browser.js

@@ -0,0 +1 @@
+export default { activate() {} };

examples/plugins/vault-scratchpad/netcatty.plugin.json

@@ -0,0 +1,23 @@
+{
+  "manifestVersion": 1,
+  "id": "com.netcatty.vault-scratchpad",
+  "name": "vault-scratchpad",
+  "displayName": { "en": "Vault Scratchpad", "zh-CN": "Vault 草稿板" },
+  "version": "0.1.0",
+  "publisher": "netcatty",
+  "license": "GPL-3.0-or-later",
+  "engines": { "netcatty": ">=0.0.0", "api": ">=0.1.0-internal.1 <0.2.0" },
+  "features": { "required": ["views.vault-pages"] },
+  "main": { "browser": "browser.js" },
+  "activationEvents": ["onView:com.netcatty.vault-scratchpad.page"],
+  "permissions": { "required": ["views"] },
+  "contributes": {
+    "views": [{
+      "id": "com.netcatty.vault-scratchpad.page",
+      "title": { "en": "Scratchpad", "zh-CN": "草稿板" },
+      "location": "vault-page",
+      "entry": "page.html",
+      "order": 10
+    }]
+  }
+}

examples/plugins/vault-scratchpad/page.css

@@ -0,0 +1,5 @@
+:root { color-scheme: light dark; font-family: system-ui, sans-serif; }
+body { margin: 0; padding: 24px; } main { max-width: 720px; margin: auto; }
+textarea { display: block; box-sizing: border-box; width: 100%; margin: 12px 0; padding: 10px; font: inherit; }
+button { padding: 8px 12px; margin: 0 8px 0 0; font: inherit; }
+#status { min-height: 1.5em; }

examples/plugins/vault-scratchpad/page.html

@@ -0,0 +1,7 @@
+<!doctype html>
+<html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width,initial-scale=1">
+<title>Vault Scratchpad</title><link rel="stylesheet" href="page.css"></head>
+<body><main><h1>Scratchpad</h1><p>This page stores only text you type here, in this plugin's own view state. It cannot read Vault hosts, notes, credentials, sessions or the clipboard.</p>
+<label for="draft">Synthetic draft</label><textarea id="draft" maxlength="4096" rows="8" disabled></textarea>
+<button type="button" id="save" disabled>Save draft</button><button type="button" id="clear" disabled>Clear draft</button>
+<p id="status" role="status">Loading your plugin draft…</p></main><script src="page.js"></script></body></html>

examples/plugins/vault-scratchpad/page.js

@@ -0,0 +1,25 @@
+"use strict";
+/* global document, window */
+const draft = document.getElementById("draft");
+const status = document.getElementById("status");
+let busy = false;
+async function save(clear) {
+  if (busy) return;
+  busy = true;
+  try {
+    const text = clear ? "" : draft.value;
+    await window.netcattyView.setState({ version: 1, text });
+    if (clear) draft.value = "";
+    status.textContent = clear ? "Draft cleared." : "Draft saved in this plugin only.";
+  } catch { status.textContent = "Could not save this draft."; }
+  finally { busy = false; }
+}
+document.getElementById("save").addEventListener("click", () => { void save(false); });
+document.getElementById("clear").addEventListener("click", () => { void save(true); });
+window.netcattyView.getState().then((state) => {
+  if (state?.version === 1 && typeof state.text === "string" && state.text.length <= 4096) draft.value = state.text;
+  status.textContent = "Ready. Use synthetic text for this example.";
+  draft.disabled = false;
+  document.getElementById("save").disabled = false;
+  document.getElementById("clear").disabled = false;
+}).catch(() => { status.textContent = "Could not load this plugin draft."; });

packages/plugin-cli/src/manifest.ts

@@ -367,6 +367,10 @@ function validateSemantics(manifest: PluginManifest): string[] {
   }
 
   const requiredFeatures = new Set(manifest.features?.required ?? []);
+  if (manifest.contributes?.views?.some((view) => view.location === 'vault-page')
+    && !requiredFeatures.has('views.vault-pages')) {
+    errors.push('Vault pages require views.vault-pages');
+  }
   if (manifest.contributes?.commands?.some((command) => command.interactive)
     && !requiredFeatures.has('commands.interactive')) errors.push('Interactive commands require commands.interactive');
   if (manifest.icon) {

packages/plugin-cli/src/vaultPages.test.ts

@@ -0,0 +1,16 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { readFile } from 'node:fs/promises';
+import { validateManifestValue } from './manifest.js';
+import { checkPluginCompatibility } from './compatibility.js';
+
+const manifest = JSON.parse(await readFile(new URL('../../../examples/plugins/vault-scratchpad/netcatty.plugin.json', import.meta.url), 'utf8'));
+test('Vault pages require exact feature negotiation and the existing views permission', () => {
+  assert.equal(validateManifestValue(manifest).valid, true);
+  assert.equal(validateManifestValue({ ...manifest, features: {} }).valid, false);
+  assert.equal(validateManifestValue({ ...manifest, permissions: {} }).valid, false);
+  assert.equal(checkPluginCompatibility(manifest, { netcattyVersion: '1.0.0', features: [] }).compatible, false);
+  assert.equal(checkPluginCompatibility(manifest, { netcattyVersion: '1.0.0', features: ['views.vault-pages'] }).compatible, true);
+  const legacy = { ...manifest, features: {}, contributes: { views: [{ ...manifest.contributes.views[0], location: 'tab' }] } };
+  assert.equal(validateManifestValue(legacy).valid, true, 'legacy tab packages keep their contract');
+});

packages/plugin-contract/schema/plugin-contract.schema.json

@@ -1005,7 +1005,10 @@
     },
     "ViewLocation": {
       "type": "string",
-      "enum": ["aside", "panel", "tab", "modal", "settings"]
+      "enum": ["aside", "panel", "tab", "modal", "settings", "vault-page"]
+    },
+    "VaultPagesFeature": {
+      "const": "views.vault-pages"
     },
     "ViewContribution": {
       "type": "object",

packages/plugin-contract/src/generated/plugin-contract.ts

@@ -1040,6 +1040,8 @@ export type ThemeIcon = {
   name: string;
 };
 
+export type VaultPagesFeature = "views.vault-pages";
+
 export type ViewContribution = {
   id: ContributionId;
   title: LocalizedText;
@@ -1051,6 +1053,6 @@ export type ViewContribution = {
   retainContextWhenHidden?: boolean;
 };
 
-export type ViewLocation = "aside" | "panel" | "tab" | "modal" | "settings";
+export type ViewLocation = "aside" | "panel" | "tab" | "modal" | "settings" | "vault-page";
 
 export type WireIntegerLimits = {"maxSafeInteger":9007199254740991};

packages/plugin-contract/src/index.ts

@@ -55,4 +55,5 @@ export const PLUGIN_NETWORK_CREDENTIAL_LEASE_FEATURE = "network.credential-lease
 
 export const PLUGIN_HOST_INTERACTION_FEATURE = "host.interactions" as const satisfies import("./generated/plugin-contract.js").HostInteractionFeature;
 
+export const PLUGIN_VAULT_PAGES_FEATURE = "views.vault-pages" as const satisfies import("./generated/plugin-contract.js").VaultPagesFeature;
 export const PLUGIN_INTERACTIVE_COMMAND_FEATURE = "commands.interactive" as const satisfies import("./generated/plugin-contract.js").InteractiveCommandFeature;

packages/plugin-sdk/src/index.ts

@@ -930,4 +930,5 @@ export function throwIfCancellationRequested(token: CancellationToken): void {
 export { PLUGIN_NETWORK_CREDENTIAL_LEASE_FEATURE } from "@netcatty/plugin-contract";
 
 export { PLUGIN_HOST_INTERACTION_FEATURE } from "@netcatty/plugin-contract";
+export { PLUGIN_VAULT_PAGES_FEATURE } from "@netcatty/plugin-contract";
 export { PLUGIN_INTERACTIVE_COMMAND_FEATURE } from "@netcatty/plugin-contract";