Model switcher shows "retry loading models" state after conversation starts

After a conversation starts, the model switcher bar displays a "retry loading models" state, preventing model switching during an active conversation.

| Field | Value |
| --- | --- |
| App version | 1.1.12 |
| OS | macOS 26.6.2 |
| Theme | GitHub |
| Path | /chat |
| Tenure | Week 2 |

Reproduce the issue in the /chat path using app version 1.1.12 by starting a conversation and opening the model switcher. Trace the model-switcher loading and retry state to determine why models are unavailable after conversation start. Done means the switcher remains usable and allows changing models during an active conversation.

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