ecd444b53b
With reduce motion on, selecting a new altitude jumps (autoScrub's reduced branch → setPos) and skips the segment that would re-roll the destination clip, so activeClipId stayed on the previous altitude's clip and the video didn't change. Self-heal at the landing point: if the landed altitude's pool doesn't contain activeClipId, pickPoolClip a fresh one. TDD: new altitude-lock e2e. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>