UPDATE 2025-11-30: I can now successfully add Firebase Authentication using the email/password sign-in method to any app I build in Google AI Studio. It’s not exactly rocket science, but it does involve several steps and required thoroughly studying the documentation. The apps are deployed using Google AI Studio’s built-in Cloud Run service, so there was no need to set up any backend, aside from Firebase, of course.
Still, my feature request stands, adding Firebase Authentication (and data storage) needs to become far simpler.