- Fetch stream URL on asset open; show <video> element for mp4/hls
- Use hls.js for live HLS streams (loaded via CDN in index.html)
- Sync video play/pause/seek/timeupdate to React state
- Show loading state while fetching stream, status message when unavailable
- Add Retry processing button for error-status assets
- totalMs derived from video metadata when available, falls back to parseDuration