- Add management command to recalculate quantity_reserved for all Stock records
- Add signals to automatically update Stock when Reservation changes
- Implement post_save signal for Reservation creation/updates
- Implement post_delete signal for Reservation deletion
- Both signals call Stock.refresh_from_batches() to recalculate quantities
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
