[Feature]: preview Resizer of ` ```tsx preview="iframe-follow"`

### What problem does this feature solve?

resize the iframe size

### What does the proposed API look like?

<img width="718" height="621" alt="Image" src="https://github.com/user-attachments/assets/0ee511da-090a-4170-a740-6f323ca4f0fa" />

No configuration required, only UI is displayed