Fixed git panel not update after commit or switch branch on Linux.

On macOS and Windows, the watcher implementation recursively watches
subdirectories.
On Linux, the watcher is non-recursive.

In Git worktree scenarios, only `<project>/.git` is watched, but the
actual worktree Git directory
`<project>/.git/worktrees/<worktree>`  is not.
Therefore, Git operations such as commits or branch switches inside a
worktree do not emit watcher events on Linux, causing the Git panel to
stay out of sync.

Release Notes:
- Fixed git panel not update after commit or switch branch on Linux with
git worktrees.