Allow selecting a configured provider in model/list (#59776)

## Why

Clients need to list models for a configured provider other than the app-server's startup default.

## What changed

Add an optional `modelProvider` parameter to `model/list` and expose it in the generated schemas and client types. Explicit selections use provider definitions loaded at startup and respect current managed provider requirements. Unknown providers return a structured `modelProviderNotConfigured` error.

Use a temporary catalog when selecting another provider, preserving the default catalog and its disk cache while retaining runtime authentication. Requests without a selector keep the existing provider and caching behavior.

## Testing

Add coverage for provider selection, preservation of the default catalog and disk cache, unknown-provider errors, managed requirement enforcement, and runtime authentication for temporary catalogs.

GitOrigin-RevId: 6092df9f6141810c6ac215a8e1fb601f77e54747

codex-rs/exec/src/daybreak.rs

@@ -50,6 +50,7 @@ pub(crate) async fn program_for_turn(
                     cursor,
                     limit: None,
                     include_hidden: Some(true),
+                    model_provider: None,
                 },
             })
             .await;