Beat-driven speed ramp, freeze-frame hit, and hard cut for music-led
promos and montages. Contributed as #2957; applied here as content so the
whole catalog set lands together.
Verified by rendering: 6s, clean, deterministic (the one Math.random hit
is a comment above a fixed pattern array). Opaque root, so no demo.html
is needed for its catalog preview.
Co-authored-by: akiyoshisan1218 <akiyoshisan1218@users.noreply.github.com>
ukimsanov