Enhanced test coverage includes `repr` methods, model functionality, and validation logic for key models like `GiftItem`, `GiftCategory`, `EventMedia`, `RSVP`, and `GiftPurchase`. Refactored and added fixtures to support comprehensive testing scenarios. Addresses validation for gift reordering and updates `EventMedia` representation format for consistency.
Introduce a `validate_display_order` method to ensure a default value of 0 for `display_order`. Extend testing infrastructure with fixtures and unit tests for `EventMedia` to validate properties, metadata, and default behaviors.
