fix: shift Freemode 3D arena down to Y=0 to prevent buried tiles, remove deprecated mesh elevation hacks

scenes/main.gd

@@ -165,6 +165,12 @@ func _instantiate_3d_arena(scene_path: String):
 		if arena_scene:
 			var arena_instance = arena_scene.instantiate()
 			arena_instance.name = "ArenaEnvironment3D"
+			
+			if "freemode" in scene_path:
+				# The Freemode Terrainv2.gltf has its floor physically modeled at Y=0.28.
+				# Shift it down so the visual floor aligns with Y=0.0 where players and gridmap items live.
+				arena_instance.position.y = -0.28
+				
 			add_child(arena_instance)
 			move_child(arena_instance, 0)
 			print("Instantiated 3D Arena: ", scene_path)
@@ -186,22 +192,9 @@ func _hide_ground_tiles():
 func _setup_effect_elevation():
 	var em = get_node_or_null("EnhancedGridMap")
 	if em and em.mesh_library:
-		# USER REQUEST: Do not apply visual Y-elevation for walls in Stop n Go mode
-		if LobbyManager.game_mode == "Stop n Go":
-			print("[Main] Stop n Go mode detected: Skipping effect elevation for walls.")
-			return
-
-		var ml = em.mesh_library.duplicate()
-		
-		# Height 0.8: Above 3D arena, but below pickups (Y=1.0)
-		var lift_transform = Transform3D().translated(Vector3(0, 0.28, 0))
-
-		# Lift Wall (4) and Freeze (5)
-		ml.set_item_mesh_transform(4, lift_transform)
-		ml.set_item_mesh_transform(5, lift_transform)
-		
-		em.mesh_library = ml
-		print("[Main] MeshLibrary elevation applied: Wall(4) and Freeze(5) at Y=0.8")
+		# Since the Freemode arena is now shifted to Y=0.0, we no longer need to lift 
+		# Wall(4) and Freeze(5) meshes by 0.28 to match the old floor height!
+		pass
 
 	# Force gridmap cell size to match player logic (1, 0.05, 1) - >0.001 to avoid errors
 	if not em:
@@ -1276,7 +1269,7 @@ func _create_static_setup(pos: Vector2i, tekton_id: int, shape_idx: int):
 						if "cell_size" in enhanced_gridmap:
 							world_pos = Vector3(
 								pos.x * enhanced_gridmap.cell_size.x + enhanced_gridmap.cell_size.x / 2,
-								0.28, # Match the 0.28 elevation of the arena floor
+								0.0, # Floor is now at 0.0 after arena shift
 								pos.y * enhanced_gridmap.cell_size.z + enhanced_gridmap.cell_size.z / 2
 							)
 						stand.global_position = world_pos