Using /model config wipes all settings #4431

Describe the bug

In v1.0.79 when setting a user-wide model via "/config model" it completely wipes all settings in "/.copilot/settings.json".

Affected version

No response

Steps to reproduce the behavior

1. Use /config model and select a model
2. settings.json is overwritten with only { "model": "<selected_model>" }

Expected behavior

No response

Additional context

• macOS