Additional issue — OAuth redirect shows app.base44.com in address bar:

During the Google login flow on a custom domain, the address bar briefly shows app.base44.com as the redirect passes through Base44's servers. Even though it's momentary, users notice it and it breaks the branded experience — they see a completely different domain mid-login which looks unprofessional and could raise trust concerns for a financial tool.

Expected behaviour: The entire login flow should stay within the custom domain or pass through a neutral Google URL only, never exposing app.base44.com to the end user.