feat: StartOffset

- 实现startOffset
- 修复EndOffset = 0 + 循环播放时，音乐会大量重复播放的错误。
- 增加数据校验和 BeatClock 联动。StartOffset不正确时停止bar+级 callback。
- BeatClock 现在会在每次重新播放时重启，以解决EndOffset配置错误被舍弃时，拍子对不上的问题。

Assets/Scripts/OCES/Audio/HandWritten/LongAudio/LongAudioContainerPlayer.cs

@@ -24,7 +24,7 @@ namespace OCES.Audio
         /// 开始播放Container时触发 音乐回调系统
         /// container本身，继承来的bpm，进入时刻的dspTime
         /// </summary>
-        internal event Action<MusicContainer, float, double> OnContainerEntered;
+        internal event Action<MusicContainer, float, double> OnContainerEntered, OnContainerLooped;
         internal event Action<MusicContainer> OnBlendError;
 
         // Sequence Step 模式的全局游标，key = containerId
@@ -119,6 +119,7 @@ namespace OCES.Audio
                 if (handle.Cancelled) yield break;
 
                 loopsCompleted++;
+                OnContainerLooped?.Invoke(container, effectiveBpm, AudioSettings.dspTime);
 
                 // -1 = 无限循环，一直重复
                 if (container.LoopCount == -1)
@@ -352,6 +353,7 @@ namespace OCES.Audio
             source.loop   = false;
             source.volume = volumeScale;
             source.Play();
+            Debug.Log($"[LongAudioContainerPlayer] Playing {segment.Name} at {AudioSettings.dspTime}");
 
             if (isLoop && segment.StartOffset > 0)
             {