Idle is a resting pose (only eye/mouth/fin micro-motion). Swapped the base loop to
Swim1_norm — a ~2.5s swim cycle with ZERO root drift (verified via trim-clip.mjs), so
UB undulates continuously without traveling off-screen. Generalized the trimmer
(tools/glb-split/trim-clip.mjs: extract any [start,end] range, rebased to 0, + drift report).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
