Add test shader for godrays, use rigidbodies to put all spawned items on the ground

Zennysoft.Game.Ma/src/map/dungeon/code/MonsterRoom.cs

@@ -58,7 +58,7 @@ public partial class MonsterRoom : DungeonRoom
 
       var selectedItem = database.PickItem<InventoryItem>();
       var duplicated = selectedItem.Duplicate((int)DuplicateFlags.UseInstantiation) as Node3D;
-      duplicated.Position = new Vector3(spawnPoint.Position.X, -0.5f, spawnPoint.Position.Z);
+      duplicated.Position = new Vector3(spawnPoint.Position.X, -1.5f, spawnPoint.Position.Z);
       AddChild(duplicated);
     }
   }