V20O TEST RESULTS

- Base used: V20N stable full build
- JS syntax: PASS (node --check app.js)
- UI patch: PASS (index contains addCameraBtn)
- Camera helpers inserted: PASS
- Media delete cleanup for camera stream: PASS

Manual smoke targets:
1. Open app
2. Click 📷 Camera
3. Allow camera permission
4. Confirm camera appears in Media Library with CAM badge
5. Assign camera to a layer and verify live render on stage/projector
