- Deleted `manage.py` and related classes
- Removed unused `PendingManageAction` and repository calls
- Updated references to obsolete manage features in tests:
- Deleted `test_statistics.py`
- Deleted `test_cron.py`
- Deleted `test_kurigram_compat.py`
- Cleaned up outdated functionality for managing questions, schedules, and statistics via `/manage`.
