Convert handle_network_failure and handle_download_failure from instance methods to static methods. Hardcode retry params (max_retries, delays) instead of using instance state. Improves testability and removes implicit dependencies.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
- Add series context helpers: prepare_series_context, get_series_by_key, filter_series_by_missing_episodes
- Update module docstring with identifier convention documentation
- Add unit tests for new series context helper functions
- Update infrastructure.md with template helpers documentation
- Mark Phase 4 (API Layer) as complete