- Add --force-ipv4 and retry flags to yt-dlp background downloads
- Clean stale cache dirs on startup and before new downloads
- Notify and drain pending card updates when cache download fails
- Fix generateAudio/generateImage config checks (missing = enabled)
- Add `youtube.mediaCache.mode` config option (`direct` | `background`)
- Resolve EDL stream URLs to single audio/video URLs before ffmpeg extraction
- Pass reconnect, user-agent, and safe headers to ffmpeg for remote streams
- Add background yt-dlp media cache with fallback to direct extraction
- Introduce `MediaInput` structured type replacing bare path strings