Adds extensive test suite covering CLI notifications, auth service,
file utilities, networking, AniList API integration, mappers, API
factory, MPV player, and selector implementations. Includes 900+ lines
of test code covering main workflows and edge cases. Minor refactor
to improve dict type safety in AniList API client.
- CLI and service layer tests
- Utility function tests
- Media API and mapper tests
- Player and selector factory tests
