App not automatically sign out if session has expired

## Description

I believe I experienced this at least once, but it was a while ago. The app didn't automatically sign me out after my session expired. It still showed my profile information, but my progress wasn't being saved. Logging out and back in resolved the issue.

We have a user who seems to be experiencing the same issue: https://forum.freecodecamp.org/t/account-suddenly-cleared-and-lost-2-certifications-mobile-bugs-too/796761.

No file or test is named. Start by reproducing the expired-session state described in the issue and compare it with the linked forum report, then trace the mobile app's authentication and session handling. Done means the app signs out or clearly prompts the user when the session expires, without displaying stale profile data or silently losing progress.

Written by the indexing model from the issue text.