Add comprehensive integration and API tests:
- Integration tests for SQLAlchemyPostRepository (34 tests)
- API tests for posts endpoints and error handlers (22 tests)
- Unit tests for PublishPostUseCase and ListPostsUseCase
- Unit tests for SessionTransactionManager
Also register generic exception handler in error_handler.py
All 167 tests pass, coverage now meets CI threshold of 70%
- Add AI code generation requirements to AGENTS.md
- Add module-level docstrings to all 46 Python modules
- Add detailed Google-style docstrings to all classes and functions
- Remove all inline comments following self-documenting code principle
- Include Args, Returns, Raises sections in function docstrings
- Add Attributes and Examples sections to class docstrings