Stream subtitles arrive as URLs and are downloaded, never piped through ffmpeg, so demanding an ffmpeg install up front broke stream syncs (and CI, which has no ffmpeg). Resolution is now lazy, scoped to embedded tracks.
- Download URL-loaded subtitle tracks (Aniyomi extension streams, Jellyfin) to a temp file first, reusing mpv's own request headers, instead of rejecting them with "Subtitle file not found"
- Pass mpv's headers through to ffmpeg for internal track extraction from streams too
- Auto-discover alass/ffsubsync/ffmpeg on PATH and common install prefixes when the config path is empty, instead of a hard-coded /usr/bin fallback that never exists on macOS
- Log subsync failures to the app log, not just a toast that vanishes in seconds
- Update docs-site and README credits for the new behavior
sudacode
