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.
Integrate `Logger` for consistent logging in services like `reports`, `categories`, `users`, `contents`, and more. Introduce caching capabilities with `CacheInterceptor` and manual cache clearing logic for categories, users, and contents. Add request throttling to critical auth endpoints for enhanced rate limiting.
Added unit tests for the `api-keys`, `auth`, `categories`, `contents`, `favorites`, `media`, and `purge` services to improve test coverage and ensure core functionality integrity.
Implemented CategoriesModule with controller, service, and DTOs for managing categories. Includes endpoints for creation, retrieval, updating, and deletion, integrated with database logic.
