fix: defer worktree git watch subscription until after worktree exists

registerPendingWorktreeWorkspace was subscribing the WorkspaceGitService
before the worktree directory existed on disk, caching a stale isGit:false
snapshot. When background reconciliation ran, it consumed the stale cache,
overwrote the correct workspace record with a wrong projectId, and briefly
showed the worktree as a standalone project in the sidebar.

Move syncWorkspaceGitWatchTarget from registerPendingWorktreeWorkspace into
handleCreatePaseoWorktreeRequest, called after createAgentWorktree, so the
first snapshot sees the real worktree — one subscribe, one load, no stale
cache to race against.

packages/server/src/server/session.ts

@@ -5880,8 +5880,6 @@ export class Session {
         buildPersistedWorkspaceRecord: (input) => this.buildPersistedWorkspaceRecord(input),
         buildProjectPlacement: (cwd) => this.buildProjectPlacement(cwd),
         projectRegistry: this.projectRegistry,
-        syncWorkspaceGitWatchTarget: (cwd, syncOptions) =>
-          this.syncWorkspaceGitWatchTarget(cwd, syncOptions),
         workspaceRegistry: this.workspaceRegistry,
         archiveProjectRecordIfEmpty: (projectId, archivedAt) =>
           this.archiveProjectRecordIfEmpty(projectId, archivedAt),
@@ -6269,6 +6267,8 @@ export class Session {
         emit: (message) => this.emit(message),
         registerPendingWorktreeWorkspace: (options) =>
           this.registerPendingWorktreeWorkspace(options),
+        syncWorkspaceGitWatchTarget: (cwd, syncOptions) =>
+          this.syncWorkspaceGitWatchTarget(cwd, syncOptions),
         sessionLogger: this.sessionLogger,
         runWorktreeSetupInBackground: (options) => this.runWorktreeSetupInBackground(options),
       },

packages/server/src/server/worktree-session.ts

@@ -87,7 +87,6 @@ type RegisterPendingWorktreeWorkspaceDependencies = {
   }) => PersistedWorkspaceRecord;
   buildProjectPlacement: (cwd: string) => Promise<ProjectPlacementPayload>;
   projectRegistry: Pick<ProjectRegistry, "get" | "upsert">;
-  syncWorkspaceGitWatchTarget: (cwd: string, options: { isGit: boolean }) => Promise<void>;
   workspaceRegistry: Pick<WorkspaceRegistry, "get" | "upsert">;
   archiveProjectRecordIfEmpty: (projectId: string, archivedAt: string) => Promise<void>;
 };
@@ -111,6 +110,7 @@ type HandleCreatePaseoWorktreeRequestDependencies = {
     worktreePath: string;
     branchName: string;
   }) => Promise<PersistedWorkspaceRecord>;
+  syncWorkspaceGitWatchTarget: (cwd: string, options: { isGit: boolean }) => Promise<void>;
   sessionLogger: Logger;
   runWorktreeSetupInBackground: (options: {
     requestCwd: string;
@@ -535,9 +535,6 @@ export async function registerPendingWorktreeWorkspace(
 
   await dependencies.projectRegistry.upsert(nextProjectRecord);
   await dependencies.workspaceRegistry.upsert(nextWorkspaceRecord);
-  await dependencies.syncWorkspaceGitWatchTarget(workspaceId, {
-    isGit: placement.checkout.isGit,
-  });
 
   if (
     existingWorkspace &&
@@ -593,6 +590,8 @@ export async function handleCreatePaseoWorktreeRequest(
       paseoHome: dependencies.paseoHome,
     });
 
+    await dependencies.syncWorkspaceGitWatchTarget(worktreePath, { isGit: true });
+
     const descriptor = await dependencies.describeWorkspaceRecord(workspace);
     dependencies.emit({
       type: "create_paseo_worktree_response",