## What changed
- Add `modelProvider/list` to return OpenAI and explicitly configured providers, provider-specific settings, and the selected default provider.
- Report `canEdit` and `canChangeDefault` based on configuration requirements, layer precedence, and whether user configuration is enabled.
- Describe gateway authentication without resolving credentials, and omit endpoint URLs that are unsuitable for display.
- Document the API and update generated JSON schemas, TypeScript types, and Python models.
## Testing
Add app-server tests for provider discovery, authentication modes, unsafe URL suppression, and configuration editability, plus a Python wire-format round-trip test.
GitOrigin-RevId: 8ba26637cd6bdd075e0e815e88aeeb04c53a2364
