Codex plan badge stays stale after downgrade, and mobile hides the model-access error

My ChatGPT subscription temporarily dropped from Pro to Free. T3’s Providers page still showed ChatGPT Pro 20x Subscription, but my selected default model, GPT-6 Astra, no longer worked.

Desktop showed:

The 'gpt-6-astra' model is not supported when using Codex with a ChatGPT account.

The all-project default subsequently showed Terra. I couldn’t tell whether the saved default changed or T3 displayed a fallback.

On Android, the thread list showed Error, but opening the same thread showed only Worked for 3.2s, with no visible error message or explanation.

I’ve since resubscribed and Astra works again. The issue is how T3 handles the temporary loss of model access:

• The account badge should reflect the changed plan.
• If the default model becomes unavailable, T3 should explain that and clearly indicate any fallback.
• The opened mobile thread should show the actionable error and label the turn as failed.

Environment: T3 Code Nightly 0.0.41-nightly.20260908.1400, macOS host, Codex CLI 0.153.4, Android client. Android build not captured.

Start by reproducing the temporary plan downgrade described in the issue, then trace the Providers page, default-model handling, and Android thread-detail rendering. Compare the thread-list error with the opened thread and verify that the plan badge, fallback explanation, actionable error, and failed-turn state remain consistent when model access is lost.