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.