[Bug]: Model error messages render as broken raw JSON in the UI

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/desktop

Steps to reproduce

Instead of rendering as a normal error message, it shows up in a weird broken layout, with some of the message appearing duplicated or cut off.

1. Open T3 Code on Arch Linux with Qtile.
2. Trigger a model-related error in the composer/chat UI.
3. Observe how the error is displayed.

Expected behavior

T3 Code renders model error messages incorrectly as raw JSON / broken text instead of a readable error banner. The error text appears visually garbled and partially clipped in the UI.

A clean, readable error message should appear in the UI, with proper formatting and no raw JSON leaking into the chat/composer area.

Actual behavior

The error is shown as raw JSON-like text and appears broken/clipped, for example:

{"type":"error","status":400,"error":{"type":"invalid_request_error","message":"The 'gpt-5.3-codex' model is not supported when using Codex with a ChatGPT account."}}

This seems like a UI rendering / layout issue rather than the API error itself. The error payload is being displayed directly in the interface and the container sizing/overflow looks wrong on this setup. I attached a screenshot showing the exact rendering issue.

Impact

Cosmetic issue

Version or commit

0.0.28

Environment

Arch Linux with Qtile WM.

Screenshots, recordings, or supporting files

2026-07-06_22-59.png

Workaround

No response

Start in apps/desktop and reproduce the model-related error from the composer/chat UI using the payload shown in the issue. Trace where that error is rendered and verify that the completed change displays a readable error banner without raw JSON, duplication, clipping, or broken layout.