feat: add PlayOnTrigger for music-synced audio playback

- Add PlayOnTrigger method to AudioSystem for scheduling audio playback on music sync events (beat/bar/grid)
- Rename ButtonInvoker to SetStateBind for better clarity
- Update PlaySoundBind to support both direct playback and trigger-based playback with callback flags
- Add CallbackFlags enum (MusicSyncBeat, MusicSyncBar, MusicSyncGrid)
- Update Metronome demo to use new callback flag naming convention
- Add test audio file sfx_notice_test.wav
- Update scene UI to demonstrate PlayOnTrigger functionality

Assets/Scripts/OCES/Metronome.cs

@@ -3,6 +3,10 @@ using UnityEngine;
 
 namespace OCES
 {
+    /// <summary>
+    /// Drag this component to any game object.
+    /// Then you will get a metronome :) 
+    /// </summary>
     public class Metronome : MonoBehaviour
     {
         void Start()
@@ -10,17 +14,17 @@ namespace OCES
             AudioSystem.Instance.OnBeat += u =>
             {
                 AudioSystem.Instance.Play(52);
-                Debug.Log($"Container {u} is OnBeat");
+                Debug.Log($"Container {u} is MusicSyncBeat");
             };
             AudioSystem.Instance.OnBar += u =>
             {
                 AudioSystem.Instance.Play(53);
-                Debug.Log($"Container {u} is OnBar");
+                Debug.Log($"Container {u} is MusicSyncBar");
             };
             AudioSystem.Instance.OnGrid += u =>
             {
                 AudioSystem.Instance.Play(54);
-                Debug.Log($"Container {u} is OnGrid");
+                Debug.Log($"Container {u} is MusicSyncGrid");
             };
         }
     }