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.
Optimized import order, applied consistent formatting, and improved readability in various modules, including `contents`, `media`, and `auth` services.
Added AuthModule with services, controllers, and guards for authentication. Implements session management, role-based access control, 2FA, and DTOs for user login, registration, and token refresh.
