feat: Implement core lobby system including UI, player management, and game mode settings.

scenes/main.gd

@@ -1286,7 +1286,8 @@ func create_bot_with_state(bot_id: int, pos: Vector2i, p_score: int, p_goals: Ar
 
 func _on_host_disconnected():
 	"""Called when the host leaves. Returns clients to the main menu."""
-	print("[Main] Host disconnected. Match terminated. Returning to lobby...")
+	print("[Main] Host disconnected. Match terminated. Cleaning up and returning to lobby...")
+	LobbyManager.leave_room()
 	get_tree().change_scene_to_file("res://scenes/lobby.tscn")
 
 func _on_rematch_starting():
@@ -1575,6 +1576,14 @@ func sync_grid_item(x: int, y: int, z: int, item: int):
 			# OR Layer 1 is already a wall (4)
 			if f0 in [4, -1] or f1 == 4:
 				return
+				
+			# TEKTON DOORS: Prevent placing items on portal doors
+			if LobbyManager.is_game_mode(GameMode.Mode.TEKTON_DOORS):
+				var doors = get_tree().get_nodes_in_group("PortalDoors")
+				for door in doors:
+					var door_grid = enhanced_gridmap.local_to_map(enhanced_gridmap.to_local(door.global_position))
+					if door_grid.x == x and door_grid.z == z:
+						return
 
 		enhanced_gridmap.set_cell_item(Vector3i(x, y, z), item)
 		# Force visual update
@@ -1601,6 +1610,17 @@ func sync_grid_items_batch(data: Array):
 			if f0 in [4, -1] or f1 == 4:
 				continue
 				
+			# TEKTON DOORS: Prevent placing items on portal doors
+			if LobbyManager.is_game_mode(GameMode.Mode.TEKTON_DOORS) and y == 1:
+				var doors = get_tree().get_nodes_in_group("PortalDoors")
+				var on_door = false
+				for door in doors:
+					var door_grid = enhanced_gridmap.local_to_map(enhanced_gridmap.to_local(door.global_position))
+					if door_grid.x == x and door_grid.z == z:
+						on_door = true
+						break
+				if on_door: continue
+				
 		enhanced_gridmap.set_cell_item(Vector3i(x, y, z), item)
 		
 	# Force visual update ONCE after batch
@@ -2084,12 +2104,8 @@ func _on_back_to_menu_pressed():
 	"""Return to lobby/main menu and clean up game state."""
 	print("[Main] Returning to lobby...")
 	
-	# Proper ordered cleanup to avoid ghost players
-	GameStateManager.end_game()
-	LobbyManager.reset()
-	
-	# Properly disconnect from Nakama match
-	_cleanup_multiplayer()
+	# Proper ordered cleanup to avoid ghost players and desync
+	LobbyManager.leave_room()
 	
 	# Small delay to let cleanup settle
 	await get_tree().create_timer(0.2).timeout
@@ -2357,8 +2373,8 @@ func _on_settings_pressed():
 
 func _on_quit_match_pressed():
 	get_tree().paused = false # Ensure unpaused when returning to menu
-	# Properly disconnect from Nakama match
-	_cleanup_multiplayer()
+	# Properly disconnect from Nakama and clear lobby state to prevent desync
+	LobbyManager.leave_room()
 	# Return to lobby or main menu
 	get_tree().change_scene_to_file("res://scenes/lobby.tscn")