Play animation's blend is given in seconds, not in frames of the new animation (#106)

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/runtime/systems/AnimationSystem.ts

@@ -7,7 +7,6 @@ import {
   blendShare,
   blends,
   blendValue,
-  fpsOf,
   isPositionRow,
   playbackOf,
   trackWriteAt,
@@ -73,7 +72,7 @@ export class AnimationSystem implements System {
         if (blend) blend.elapsed += dt;
       }
       const head = animationPlayheadAt(asset, player.time);
-      const share = blend ? blendShare(blend, fpsOf(asset)) : 1;
+      const share = blend ? blendShare(blend) : 1;
       for (const b of bindings) {
         let value = trackWriteAt(b.track, b.kind, head.frame, player.bases[b.base], head.reverse);
         if (value === undefined) continue;