## Problem
- On Linux, non-recursive watcher registrations remained path-cached
after deleting and recreating a directory in the same session.
- The recreated directory was not re-watched, so newly created child
entries under that path could be missing.
## Summary
- Remove directory watcher registrations when worktree paths are removed
from snapshot state.
- Ensure recreated directories can be watched again on Linux by allowing
`scan_dir` to re-add fresh watches.
- Add a Linux integration regression test for directory delete/recreate
path reuse and child file creation.
## Testing
- `cargo test -p project --features test-support --test integration
test_recreated_directory_receives_child_events -- --exact`
- `cargo test -p project --features test-support --test integration
test_rescan_and_remote_updates -- --exact`
## Related
- #46709
Release Notes:
- Fixed Linux worktree file watching so child entries appear after
deleting and recreating a directory at the same path.
Chriss4123
c3f05a7060