Playlist handling:
- Playlists are split into individual jobs at enqueue time
- Each entry downloads independently with its own progress tracking
- Private/unavailable playlist entries detected and reported in preview
- Individual jobs use noplaylist=True to prevent re-expansion
Session persistence:
- App.vue now calls fetchJobs() on mount to reload history from backend
- Download history survives page refresh via session cookie
Audio detection:
- Domain-based detection for known audio sources (bandcamp, soundcloud)
- Bandcamp albums now correctly trigger audio-only mode
Bug fixes:
- ProgressEvent accepts float for downloaded_bytes/total_bytes (fixes
pydantic int_from_float validation errors from some extractors)
- SSE job_update events now include error_message for failed jobs
- Fixed test_health_queue_depth test to use direct DB insertion instead
of POST endpoint (avoids yt-dlp side effects in test env)
