显示修正

scripts/verify-sub-emitter-timeline.mjs

@@ -95,6 +95,8 @@ const source = `
   frames = store.recalcTotalFrames()
   assert(frames === Math.ceil(4 * 30) + 1, '最坏情况总长度计算错误：' + frames)
   assert(store.playbackRange.start === 0 && store.playbackRange.end === 90, '播放范围没有停在时间条末端')
+  assert(store.contentEndFrame === 90 && store.timeline.totalFrames - 1 - store.contentEndFrame === 30,
+    '空白帧数量计算错误')
 
   console.log('子发射器时间轴校验通过：死亡/出生触发与移除引用后的总长度')
 `