- Implemented media airing schedule functionality in `media_airing_schedule.py` to fetch and display upcoming episodes with air dates and countdown timers.
- Created character selection feature in `media_characters.py` to fetch and display a list of characters, showing details upon selection.
- Updated state management to include new menu options for characters and airing schedules.
- Enhanced preview functionality to support character and airing schedule previews.
- Added necessary API methods and data models for handling character and airing schedule data.
- Introduced a new PreviewWorkerManager to handle both anime and episode preview caching.
- Implemented PreviewCacheWorker and EpisodeCacheWorker for specialized background tasks.
- Added context management for preview operations to ensure proper cleanup.
- Enhanced error handling and logging during image downloads and info text generation.
- Removed redundant caching logic and consolidated functionality into worker classes.
- Updated session management to clean up preview workers on session end.
- Removed unused utility functions and streamlined the codebase.
