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.

索引モデルが issue の本文から書いたものです。