fix: subway unloads stations on exit

src/base-environments/transition/code/fahrplan.gd

@@ -102,3 +102,7 @@ func _unparent_all_stations_except(except : Node3D):
 			current = station
 			continue
 		remove_child(station)
+
+func unload() -> void:
+	for station in stations:
+		station.queue_free()

src/base-environments/transition/code/subway_sequence.gd

@@ -22,3 +22,6 @@ func pull_save_state(save: SaveGame) -> void:
 
 	# Call parent to restore player position
 	super.pull_save_state(save)
+
+func unload() -> void:
+	$Logic/Fahrplan.unload()