Implement normalized error handling with Persian translations across all
exception types, replace legacy NestJS exceptions with AppException,
and add unit, integration, and smoke tests.
- Add error catalog with gateway-owned codes and Persian messages
- Introduce AppException wrapping normalized error envelopes
- Add translateError helper for automatic messageFa population
- Remove claims module and update provider error normalization
- Add unit tests for error contracts and helper functions
- Add integration tests for admin and inquiry endpoints
- Add smoke tests for real provider connectivity
- Add test support utilities (auth mocks, assertions, app factory)
