Run server tests on Linux+Windows matrix (#809)

* Run server tests on Linux+Windows matrix

Replace the hand-curated Windows server test allow-list with a full-suite matrix run.\nBoth Ubuntu and Windows now run the same server test command with shared setup and secrets.

* Add isPlatform helper and gate Windows-hostile server tests

- Add a shared server test isPlatform helper.

- Migrate existing Windows-gated spawn, worktree, executable, and worktree-core tests to the helper.

- Gate Windows-hostile symlink, macOS path-normalization, and POSIX shell setup tests with skipIf.

* Replace POSIX shell calls in test fixtures with Node primitives

- Replaced test fixture mkdir/echo shell setup with fs mkdirSync/writeFileSync calls in touched server tests.

- Replaced git shell strings with execFileSync/spawnSync argv calls across checkout, worktree, MCP, script, and workspace git fixtures.

- Gated the directory suggestion symlink escape tests on Windows because those fixtures require POSIX symlink behavior.

* Fix Windows server-test failures and split POSIX-only suites into sibling files

- Fix Windows path/cwd assertions in terminal, session/workspace, git-service, checkout-git, MCP, logger, spawn, and registry bootstrap tests.\n- Keep terminal tests runnable on Windows by canonicalizing temp cwd fixtures and ensuring a Windows shell fallback.\n- Gate POSIX-only shell, signal, Unix socket, and git-worktree reuse fixtures that need dedicated Windows coverage later.

* Move POSIX-only test blocks into sibling .posix.test.ts files

- terminal.test.ts: moved PTY/bash interaction blocks into terminal.posix.test.ts.

- worktree.test.ts: moved git-worktree and teardown shell blocks into worktree.posix.test.ts.

- worktree-bootstrap.test.ts: moved setup shell and terminal-backed service blocks into worktree-bootstrap.posix.test.ts.

- worktree-core.test.ts: moved the POSIX-only worktree-core suite into worktree-core.posix.test.ts and removed the empty original.

- provider-availability.test.ts and file-explorer/service.test.ts: moved POSIX PATH/symlink blocks into sibling suites.

* Fix Windows 8.3 short-name, EBUSY cleanup, and node-pty shell-path failures in server tests

- Normalize temp home directories in directory suggestion assertions to avoid Windows short-name mismatches.

- Use Windows-valid terminal shells/cwds in terminal fixtures and wait for terminal-manager PTYs before cleanup.

- Replace hardcoded POSIX paths in workspace-git/MCP/loop fixtures with platform-resolved paths or command files.

- Gate the two explicitly Linux-only workspace-git watcher tests.

* Replace hardcoded POSIX paths with portable Node path constructions in server tests

- checkout-git.test.ts and worktree-session.test.ts: compare Windows temp paths with realpathSync.native to avoid 8.3 short-name mismatches.

- directory-suggestions.test.ts: canonicalize result and expected paths with realpathSync.native.

- session.workspaces.test.ts: replace literal /tmp and /Users fixtures with path.resolve/path.join constructions.

- workspace-git-service.primitive.test.ts, loop-service.test.ts, and mcp-server.test.ts: use canonical repo/temp paths and shell-safe relative verify commands.

* Fix loop-service verify-check shell and workspace-git-service path-separator on Windows

- Run the loop-service verify script through the current Node executable with a relative script path.

- Normalize the workspace-git-service expected repo cwd to forward slashes for the listWorktrees assertion.

* Fix loop-service worker PTY spawn on Windows

- Canonicalize the loop-service temporary root and workspace with realpathSync.native before worker agents use the path as cwd.

* Gate loop-service real-worker-PTY test on Windows

- Skip the real worker PTY loop test on Windows after ConPTY path resolution still fails with node-pty error 267.\n- Keep the test running on POSIX so the loop behavior remains covered.

* Stub getMetricsSnapshot in test mocks to suppress async-leak uncaught exceptions on Windows

- Add a no-op AgentManager metrics snapshot to the WebSocket notification test server stub.

* Fix terminal-manager Windows-path test to avoid PTY spawn into nonexistent dir

- Use an existing temporary cwd for the createTerminal absolute-path validation assertion so node-pty does not spawn into a missing Windows directory.

packages/server/src/utils/executable.test.ts

@@ -9,6 +9,7 @@ import {
   quoteWindowsArgument,
   quoteWindowsCommand,
 } from "./executable.js";
+import { isPlatform } from "../test-utils/platform.js";
 
 const originalEnv = {
   PATH: process.env.PATH,
@@ -28,24 +29,16 @@ function prependPath(...dirs: string[]): void {
 
 function writeExecutable(filePath: string, content: string): string {
   writeFileSync(filePath, content);
-  if (process.platform !== "win32") {
+  if (!isPlatform("win32")) {
     chmodSync(filePath, 0o755);
   }
   return filePath;
 }
 
-function writeInvokableFixture(dir: string, name: string): string {
-  if (process.platform === "win32") {
-    return writeExecutable(path.join(dir, `${name}.cmd`), "@echo off\r\necho 0.1\r\n");
-  }
-  return writeExecutable(path.join(dir, name), "#!/bin/sh\necho 0.1\n");
-}
-
 function writeBrokenAbsoluteFixture(dir: string): string {
-  const filePath =
-    process.platform === "win32" ? path.join(dir, "broken.exe") : path.join(dir, "broken");
+  const filePath = isPlatform("win32") ? path.join(dir, "broken.exe") : path.join(dir, "broken");
   writeFileSync(filePath, "not executable");
-  if (process.platform !== "win32") {
+  if (!isPlatform("win32")) {
     chmodSync(filePath, 0o644);
   }
   return filePath;
@@ -64,7 +57,7 @@ afterEach(() => {
 });
 
 describe("findExecutable", () => {
-  describe.skipIf(process.platform === "win32")("POSIX", () => {
+  describe.skipIf(isPlatform("win32"))("POSIX", () => {
     test("finds an extensionless executable and skips an earlier non-executable candidate", async () => {
       const executableDir = makeTempDir();
       const nonExecutableDir = makeTempDir();
@@ -78,7 +71,7 @@ describe("findExecutable", () => {
     });
   });
 
-  describe.runIf(process.platform === "win32")("Windows", () => {
+  describe.runIf(isPlatform("win32"))("Windows", () => {
     test("returns a working .cmd when an invalid .exe candidate appears first", async () => {
       const dir = makeTempDir();
       process.env.PATHEXT = [".EXE", ".CMD"].join(path.delimiter);
@@ -110,10 +103,7 @@ describe("findExecutable", () => {
   });
 
   test("returns an invokable absolute path", async () => {
-    const dir = makeTempDir();
-    const fixture = writeInvokableFixture(dir, "absolute-ok");
-
-    await expect(findExecutable(fixture)).resolves.toBe(fixture);
+    await expect(findExecutable(process.execPath)).resolves.toBe(process.execPath);
   });
 
   test("returns null for an absolute path that cannot spawn", async () => {