Delete orphaned worktree when deleting a thread

- Prompt to remove the worktree when a deleted thread is its only reference
- Best-effort cleanup via `api.git.removeWorktree` after thread deletion
- Add `getOrphanedWorktreePathForThread` helper with unit tests
6d9a467e75Julius Marminge committed on 2/13/2026, 6:33:40 AMparent5da67c4
3 files changedLine totals unavailable