Re-render 20 sample_window GIFs + MP4s with the trim_offset bug fixed (was showing OT-offline prefix region for windows from trimmed eps; now shows the correct post-trim region with live OT pose updating across frames).

Audit batch 3: ship .mp4 alongside every GIF for inline HF rendering (#11). 51 files, total GIF→MP4: 451→24 MB.