fix: 删除Start()中_bgAudioSource初始化+修复PlayExperimentBg调用

Assets/Scripts/UI/PageController.cs

@@ -49,13 +49,6 @@ public class PageController : MonoBehaviour
     {
         Debug.Log("=== PageController 初始化开始 ===");
 
-        // 背景音乐 AudioSource
-        var mgr = GameObject.Find("[Managers]");
-        if (mgr != null) { _bgAudioSource = mgr.AddComponent<AudioSource>(); }
-        else { _bgAudioSource = gameObject.AddComponent<AudioSource>(); }
-        _bgAudioSource.loop = true;
-        _bgAudioSource.playOnAwake = false;
-        _bgAudioSource.spatialBlend = 0f;
         // 关掉多余AudioListener（只留Main Camera的）
         var cam2 = GameObject.Find("camera2"); if (cam2 != null) { var al = cam2.GetComponent<AudioListener>(); if (al != null) al.enabled = false; }
         var cam3 = GameObject.Find("camera3"); if (cam3 != null) { var al = cam3.GetComponent<AudioListener>(); if (al != null) al.enabled = false; }
@@ -274,7 +267,7 @@ public class PageController : MonoBehaviour
     {
         Debug.Log("PageController: [ActivateExperimentObjects] 显示实验物件");
 
-        PlayExperimentBg();
+        BGMController.PlayExperimentBg();
 
         var allObjects = FindObjectsOfType<GameObject>(true);
         foreach (var go in allObjects)