Initial Unity 6 scaffold for Cat Kirby Adventures.

Add Phase A greybox vertical slice: third-person movement, forest path, checkpoints, story triggers, and light ability gate.

Assets/_Project/Scripts/Level/ILightReactive.cs

@@ -0,0 +1,9 @@
+using UnityEngine;
+
+namespace KirbyAdventures
+{
+    public interface ILightReactive
+    {
+        void OnHitByLight(Vector3 hitPoint, Vector3 direction);
+    }
+}