Changes

Init collections, adjust services & update tests

Initialize collection fields and add cascades to entities to avoid NPEs and ensure proper persistence; change ShelterEventRepository signature to use Long. Update service behaviors: improve error messages and logging in AdopterService, restrict Notification deletion to items older than 30 days and use searchNotification, increase ShelterEvent code range and add creation/delete guards and logging. Rename many test packages to co.edu.udistrital.mdp.pets.services and adapt tests (MedicalEvent and Adopter tests updated to persist related entities and collections). These changes fix null collection issues, align types for event codes, and enforce business rules around deletions.
 (commit: c99c8ec)