Itahuka Studio Program Output Patch
===================================

Replace:

studio.php
assets/studio.js

What this adds:
- Real 1280x720 Program Output canvas
- Staged guest video compositing
- Staged guest audio mixing
- Program Output publish back to LiveKit
- Existing YOLOCast target workflow remains

Important:
This creates video/audio output, but browsers still cannot push RTMP directly to YOLOCast.

Final path required:
Program Output published to LiveKit
  -> LiveKit Egress or MediaMTX bridge
  -> YOLOCast RTMP URL

How to test:
1. Open studio.php?room=itahuka-live
2. Connect operator.
3. Add at least one guest to stream.
4. Click Start Program Output.
5. Click Publish Program to LiveKit.
6. Prepare YOLOCast target.
7. Go Live.

YOLOCast will still show Offline until the LiveKit Egress/RTMP bridge is configured.
