- Add GameEndResult dataclass with winner, loser, final views, duration
- Add _map_end_reason() to map core GameEndReason to DB EndReason
(raises ValueError for unknown reasons to catch missing enum sync)
- Enhance end_game() to build replay data and return comprehensive result
- Add archive_to_history() to GameStateManager for complete game archival:
- Creates GameHistory record with replay data
- Deletes ActiveGame record
- Clears Redis cache
- All in single transaction
- Add ArchiveResult dataclass for archive operation metadata
- Add TODO for session_factory DI refactor in GameStateManager
- Update tests: 5 new end_game tests, 6 new archive_to_history tests
Phase 4 progress: 10/18 tasks complete
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
