Sign-ins time out with suspended computers

1. Sign in to CodeWorld
2. Suspend your computer, then re-open the next day.
3. Try to save a project.

You get "Oops, cannot save your project". Signing out and back in fixes it. But we should detect this and fix it ourselves, or change to the logged-out UI and inform the user.

No files, tests, or entry points are named. Reproduce the suspend-and-resume sequence, then trace the save-project request and sign-in session handling to determine how an expired session is reported. Done means the stale session is detected and either repaired or the logged-out UI clearly informs the user.

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