fix(ssh): resolve ET ssh wrapper without a host OpenSSH binary

Unit tests stub execFileSync and only found ssh via /usr/bin/ssh, so the
PATH wrapper was skipped on images without that path. Prefer an absolute
findExecutable result, then command -v, then the well-known locations.

Co-authored-by: 陈大猫 <binaricat@users.noreply.github.com>

electron/bridges/terminalBridge/etSession.cjs

@@ -832,13 +832,19 @@ main();
         try {
           // Resolve the real OpenSSH binary to an absolute path BEFORE we
           // prepend the wrapper directory to PATH. Embedding a bare `ssh`
-          // name would recurse into the wrapper forever.
-          let realSsh = process.platform === "win32"
-            ? (findExecutable("ssh") || "")
-            : "";
+          // name would recurse into the wrapper forever. findExecutable
+          // returns that bare name off Windows, so only an absolute result
+          // is usable; otherwise fall back to command -v and well-known paths.
+          let realSsh = "";
+          try {
+            const found = typeof findExecutable === "function" ? findExecutable("ssh") : "";
+            if (found && path.isAbsolute(String(found))) realSsh = String(found);
+          } catch {
+            // Fall through to command -v / well-known paths.
+          }
           if (!realSsh || !path.isAbsolute(realSsh)) {
             try {
-              const resolved = execFileSync(
+              const lookup = execFileSync(
                 process.platform === "win32" ? "where" : "sh",
                 process.platform === "win32" ? ["ssh"] : ["-c", "command -v ssh"],
                 {
@@ -847,8 +853,9 @@ main();
                   windowsHide: true,
                   env: process.env,
                 },
-              ).trim().split(/\r?\n/)[0];
-              if (resolved) realSsh = resolved;
+              );
+              const resolved = String(lookup ?? "").trim().split(/\r?\n/).find(Boolean) || "";
+              if (resolved && path.isAbsolute(resolved)) realSsh = resolved;
             } catch {
               // Fall through to common absolute locations.
             }

electron/bridges/terminalBridge/etSession.test.cjs

@@ -26,6 +26,13 @@ function makeApi(t, overrides = {}) {
     getTempFilePath: (name) => path.join(base, name),
     getTempDir: () => base,
   };
+  // Absolute stand-in for OpenSSH. prepareEtSshEnvironment must be able to
+  // inject the PATH wrapper without the host image having /usr/bin/ssh, and
+  // without the execFileSync stub (used to skip Windows icacls) answering
+  // `command -v ssh`.
+  const fakeSsh = path.join(base, "openssh", process.platform === "win32" ? "ssh.exe" : "ssh");
+  fs.mkdirSync(path.dirname(fakeSsh), { recursive: true });
+  fs.writeFileSync(fakeSsh, "#!/bin/sh\nexit 0\n");
   const osMock = {
     homedir: () => fakeHome,
     userInfo: () => ({ username: "tester" }),
@@ -53,7 +60,7 @@ function makeApi(t, overrides = {}) {
     trackSessionIdlePrompt: () => {},
     createPtyOutputBuffer: overrides.createPtyOutputBuffer
       || (() => ({ bufferData() {}, flush() {}, flushPaced() {} })),
-    findExecutable: () => "ssh",
+    findExecutable: (name) => (name === "ssh" ? fakeSsh : name),
     bundledEtClient,
   });
   return { api, base, sessions };