fix(server): keep Git observation and worktree IO off the event loop (#7943)

* fix(server): keep Git observation and worktree IO off the event loop

Resolve subscription path identities before callbacks and serialize async worktree metadata mutations by canonical ownership. Git command tracing must not probe the working directory before spawning.

* test(server): verify Git trace records without filesystem probes

* fix(server): establish Git identities at observation setup

Read-only checkout refreshes should not resolve watcher namespaces. Observation tests await setup and compare cross-workspace fan-out without depending on completion order.

* fix(server): retain literal symlink targets in Git event identity

Canonical realpaths can erase a symlink target spelling when its parent is also a symlink, such as /var on macOS. Resolve these aliases once during setup so deleted and ignored event paths still match without per-event IO.

* fix(server): preserve Windows worktree path spelling

* fix(server): retain native aliases in worktree ownership

* test(server): write Git IO trace markers asynchronously

packages/server/src/utils/checkout-git.test.ts

@@ -2859,7 +2859,7 @@ const x = 1;
       execFileSync("git", ["worktree", "add", workspaceDir, "contributor/old-change"], {
         cwd: repoDir,
       });
-      writePaseoWorktreeMetadata(workspaceDir, {
+      await writePaseoWorktreeMetadata(workspaceDir, {
         baseRefName: "main",
         changeRequestLookupTarget: {
           headRef: "old-change",
@@ -2899,7 +2899,7 @@ const x = 1;
     const workspaceDir = join(paseoHome, "worktrees", "repo", "renamed-by-agent");
     mkdirSync(join(paseoHome, "worktrees", "repo"), { recursive: true });
     execFileSync("git", ["worktree", "add", workspaceDir, "placeholder"], { cwd: repoDir });
-    writePaseoWorktreeMetadata(workspaceDir, {
+    await writePaseoWorktreeMetadata(workspaceDir, {
       baseRefName: "main",
       changeRequestLookupTarget: {
         headRef: "placeholder",
@@ -2936,7 +2936,7 @@ const x = 1;
     const workspaceDir = join(paseoHome, "worktrees", "repo", "pinned-worktree");
     mkdirSync(join(paseoHome, "worktrees", "repo"), { recursive: true });
     execFileSync("git", ["worktree", "add", workspaceDir, "feature/pinned"], { cwd: repoDir });
-    writePaseoWorktreeMetadata(workspaceDir, {
+    await writePaseoWorktreeMetadata(workspaceDir, {
       baseRefName: "main",
       changeRequestLookupTarget: {
         headRef: "feature/pinned",
@@ -2975,7 +2975,7 @@ const x = 1;
     execFileSync("git", ["worktree", "add", workspaceDir, "contributor/old-change-1"], {
       cwd: repoDir,
     });
-    writePaseoWorktreeMetadata(workspaceDir, {
+    await writePaseoWorktreeMetadata(workspaceDir, {
       baseRefName: "main",
       changeRequestLookupTarget: {
         headRef: "old-change",
@@ -2997,7 +2997,7 @@ const x = 1;
     execFileSync("git", ["worktree", "add", workspaceDir, "contributor/old-change"], {
       cwd: repoDir,
     });
-    writePaseoWorktreeMetadata(workspaceDir, {
+    await writePaseoWorktreeMetadata(workspaceDir, {
       baseRefName: "main",
       changeRequestLookupTarget: {
         headRef: "old-change",
@@ -3062,7 +3062,7 @@ const x = 1;
     execFileSync("git", ["worktree", "add", workspaceDir, "mixedowner/old-change"], {
       cwd: repoDir,
     });
-    writePaseoWorktreeMetadata(workspaceDir, {
+    await writePaseoWorktreeMetadata(workspaceDir, {
       baseRefName: "main",
       changeRequestLookupTarget: {
         headRef: "old-change",
@@ -3114,7 +3114,7 @@ const x = 1;
     execFileSync("git", ["worktree", "add", workspaceDir, "feature/gitlab-mr"], {
       cwd: repoDir,
     });
-    writePaseoWorktreeMetadata(workspaceDir, {
+    await writePaseoWorktreeMetadata(workspaceDir, {
       baseRefName: "main",
       changeRequestLookupTarget: {
         headRef: "feature/gitlab-mr",
@@ -3128,7 +3128,9 @@ const x = 1;
     const forge = createGitHubServiceRecordingPullRequestTargets({ requestedTargets });
 
     await renameCurrentBranch(workspaceCwd, "feature/renamed");
-    expect(readPaseoWorktreeMetadata(workspaceDir)?.changeRequestLookupTarget).toMatchObject({
+    expect(
+      (await readPaseoWorktreeMetadata(workspaceDir))?.changeRequestLookupTarget,
+    ).toMatchObject({
       localBranchName: "feature/renamed",
     });
     const renamedFacts = await getCheckoutSnapshotFacts(workspaceDir, { paseoHome });
@@ -3164,7 +3166,7 @@ const x = 1;
     execFileSync("git", ["worktree", "add", workspaceDir, "feature/placeholder"], {
       cwd: repoDir,
     });
-    writePaseoWorktreeMetadata(workspaceDir, {
+    await writePaseoWorktreeMetadata(workspaceDir, {
       baseRefName: "main",
       changeRequestLookupTarget: {
         headRef: "feature/placeholder",
@@ -3174,7 +3176,7 @@ const x = 1;
 
     await renameCurrentBranch(workspaceDir, "feature/generated");
 
-    expect(readPaseoWorktreeMetadata(workspaceDir)?.changeRequestLookupTarget).toEqual({
+    expect((await readPaseoWorktreeMetadata(workspaceDir))?.changeRequestLookupTarget).toEqual({
       headRef: "feature/generated",
       localBranchName: "feature/generated",
     });
@@ -3951,7 +3953,7 @@ const x = 1;
       cwd: worktree.worktreePath,
     });
 
-    const metadataPath = getPaseoWorktreeMetadataPath(worktree.worktreePath);
+    const metadataPath = await getPaseoWorktreeMetadataPath(worktree.worktreePath);
     rmSync(metadataPath, { force: true });
 
     const baseDiff = await getCheckoutDiff(worktree.worktreePath, { mode: "base" }, { paseoHome });
@@ -3970,7 +3972,7 @@ const x = 1;
       paseoHome,
     });
 
-    const metadataPath = getPaseoWorktreeMetadataPath(worktree.worktreePath);
+    const metadataPath = await getPaseoWorktreeMetadataPath(worktree.worktreePath);
     rmSync(metadataPath, { force: true });
 
     const status = await getCheckoutStatus(worktree.worktreePath, { paseoHome });