Show the router's recommended model for "Auto" before executing, with the option to override

When I select "Auto" for model selection, the request runs right away against whatever model the router picks. That works, but I never get to see which model was chosen or step in before it runs.

It would help to have the router return its recommended model for a given query first, then let me either accept it or pick a different model. So "Auto" becomes a recommendation I can confirm or overrule, rather than a decision that happens silently.

## What I'd like

- When "Auto" is selected, the router surfaces its recommended model for the current query before the request executes.
- I can accept the recommendation and run with it, or switch to another model and run with that instead.
- Optionally, a setting to keep the current behavior (auto-run immediately) for people who prefer it.

## Why

The router usually gets it right, but not always. Some queries are cheap enough that I want a smaller model, and some I know need a stronger one regardless of what the router thinks. Seeing the pick first gives me that control without giving up the convenience of Auto.

Bắt đầu bằng cách xác định luồng chọn model của Auto và điểm vào của yêu cầu router. Theo dõi nơi model được đề xuất trở nên khả dụng trước khi thực thi, sau đó xác định hành vi chấp nhận, ghi đè và tự động chạy tùy chọn; hoàn tất khi Auto không còn tự chạy im lặng khi xác nhận được bật.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.