- Add shared config.py with API URLs, regexes, timeouts, pagination
- Add GiteaClient and VikunjaClient in api_clients.py with pooled sessions
- Add APIError exception for unified HTTP error handling
- Refactor all scripts to use shared modules and http.HTTPStatus
- Rewrite unit tests to mock clients and use HTTPStatus constants
- Add tests for api_clients and config modules
- Achieve 100% test coverage