feat: Introduce DownCount feature with new models, scripts, textures, and a dedicated quiz scene.

Assets/Quiz/Scripts/DownCount/DownCountClock.cs

@@ -0,0 +1,30 @@
+
+using UdonSharp;
+using UnityEngine;
+using VRC.SDK3.UdonNetworkCalling;
+using VRC.SDKBase;
+using VRC.Udon;
+
+public class DownCountClock : UdonSharpBehaviour
+{
+    public Animator clockAnimator;
+    public AudioSource clockAudioSource;
+
+    public void StartNetworkedClock()
+    {
+        SendCustomNetworkEvent(VRC.Udon.Common.Interfaces.NetworkEventTarget.All, "StartClock");
+    }
+
+    [NetworkCallable]
+    public void StartClock()
+    {
+        if (clockAnimator != null)
+        {
+            clockAnimator.SetTrigger("StartCountdown");
+        }
+        if (clockAudioSource != null && !clockAudioSource.isPlaying)
+        {
+            clockAudioSource.Play();
+        }
+    }
+}