## What changed
When the model catalog is provided in context and model overrides are exposed, tell V2 `spawn_agent` callers to inherit the current model unless the user explicitly asks for a different model. Include this guidance even when spawn metadata is hidden.
## Testing
Extend tool-description tests to cover hidden metadata with both inline and context catalogs, and update request-level assertions for V1 and V2 model override guidance.
GitOrigin-RevId: b70b0f09b0b5987a0eccba578196b8ef7cee4baf