Backend: - POST /api/session/worktree/remove — removes a session's git worktree - Guards: stream/terminal lock, dirty/untracked without force - remove_worktree_for_session() in api/worktrees.py Frontend: - 'Remove Worktree' context menu item + confirm modal - i18n keys for all 11 locales Tests: - 5 tests: clean remove, missing worktree, no-path, route success, 404