Removes the retained-worktree store end to end: the daemon's state-dir
store, GET/DELETE /api/worktrees, `maestro worktrees list|reclaim`, the
TUI overlay behind `w`, and the web `#/worktrees` view and header link.
The kill guard stays. A forced kill and a dirty natural exit now leave
the worktree on disk untouched instead of parking it in a store, so
removing one is an ordinary `git worktree remove`. A pristine tree is
still removed on exit. DELETE /api/sessions/:id always answers 204.
The header's debug button also goes; Ctrl+Shift+D and `?hud` still
toggle the HUD.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
