R3F: slow lerp factor causes near-zero rotation at beat entry in headless testing — snap on beat change

Group rotation speed was lerped at factor 0.03 per frame toward BEAT_ROT_SPEED[beat]. Entering locked from recognition (which gates rotation to 0 during silence): after 5 headless Playwright frames (150ms each), speed was still ~0.016 rad/s vs target 0.11 rad/s. changedFrac remained near 0.

With lerp factor 0.03: speed after 5 frames = 0.11 * (1 - 0.97^5) = 0.11 * 0.141 = 0.016 rad/s.