Deleted unused e2e tests, mocks (`cuid2`, `jose`, `ml-kem`, `sha3`), and their associated jest configurations. Simplified services by ensuring proper dependency imports, resolving circular references, and improving TypeScript type usage for enhanced maintainability and testability. Upgraded Dockerfile base image to match new development standards.
Introduce repository pattern across multiple services, including `favorites`, `tags`, `sessions`, `reports`, `auth`, and more. Decouple crypto functionalities into modular services like `HashingService`, `JwtService`, and `EncryptionService`. Improve testability and maintainability by simplifying dependencies and consolidating utility logic.
Added unit tests for the `api-keys`, `auth`, `categories`, `contents`, `favorites`, `media`, and `purge` services to improve test coverage and ensure core functionality integrity.
Introduced CommonModule to centralize shared functionality. Added PurgeService for automated database cleanup and a global exception filter for unified error handling.
