- Add get_materials_to_delete_by_managers() function in db/materials_to_delete.py
- Supports querying by single manager, multiple managers, or all managers
- Uses IN clause for multi-manager queries
- Refactor DiscreteMaterialPlanCleaner to accept manager_names parameter
- Accepts str, List[str], or None (for all managers)
- Automatically normalizes parameter types in __init__
- Updates preload_data() with appropriate log messages
Co-Authored-By: Claude (glm-5) <noreply@anthropic.com>