Disclaimer: I have not published anything to App Store.
You probably have control over it, but what would the close button do? Thus I am guessing that if you publish a stand-alone app and you want the title bar, you use e.g. a NavigationView for it, or roll your own.
EDIT: oh wow, I just realized yours is almost exactly the same thing. I glanced at it and thought "Oh, it uses lots of os.path functions that I didn't know existed," but looking again it's basically exactly like my solution except using os.sep :)