Adds clear how-to documentation for changing the vision model, web
extraction model, and compression model to the user-facing docs site
(website/docs/user-guide/configuration.md).
Includes:
- Full auxiliary config.yaml example
- 'Changing the Vision Model' walkthrough with config + env var options
- Provider options table (auto/openrouter/nous/main)
- Multimodal safety warning for vision
- Environment variable reference table
- Updated the warning about OpenRouter-dependent tools to mention
auxiliary model configuration
169615abc8