feat: Implement Stop N Go game mode with phase management, mission objectives, and visual HUD elements.

scenes/lobby.gd

@@ -545,6 +545,9 @@ func _on_profile_updated() -> void:
 
 func _update_player_slots() -> void:
 	"""Update all player slot visuals based on current player list."""
+	if not multiplayer.has_multiplayer_peer():
+		return
+		
 	var players = LobbyManager.get_players()
 	var my_id = multiplayer.get_unique_id()