worktree: Don't eagerly remove watchers (#58692)

Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Closes #ISSUE

Release Notes:

- N/A or Added/Fixed/Improved ...
0c660d0cb4Ben Kunkle committed on 6/5/2026, 11:48:20 PM· committed by GitHubparente5c370b
3 files changedLine totals unavailable