- Rename CRUD layer to Repository layer throughout architecture documentation.
- Update dependency injection examples to use repository classes.
- Add async SQLAlchemy pattern for Repository methods (`select()` and transactions).
- Replace CRUD references in FEATURE_EXAMPLE.md with Repository-focused implementation details.
- Highlight repository class responsibilities and remove outdated CRUD patterns.
- Created `ARCHITECTURE.md` with an extensive overview of backend design, principles, and project structure.
- Documented key architectural layers: API, dependencies, services, CRUD, and data layers.
- Included comprehensive guidelines for database architecture, authentication/authorization, error handling, and testing strategy.
- Provided examples for each layer, security practices, and performance considerations.
- Aimed at improving developer onboarding and ensuring consistent implementation practices.
