优化碰撞识别，加入暖场帧数

src/core/particleEmitter.ts

@@ -862,4 +862,10 @@ export class ParticleEmitter extends Container {
     this._lastSeed = this.cfg.seed
     this.rng = mulberry32(this.cfg.seed >>> 0)
   }
+
+  /** 从当前重置状态向前模拟，用于时间轴第 0 帧的暖场。 */
+  warmup(frames: number, frameDuration: number) {
+    const count = Math.max(0, Math.floor(Number(frames) || 0))
+    for (let frame = 0; frame < count; frame++) this.update(frameDuration)
+  }
 }