[Requests and ideas] Add mobile device emulation

### Feature summary

Mobile emulation toggle in browser tab

### What problem are you trying to solve?

It's really nice that clickable links inside the app open inside the side pane by default, keeping me in app making it easy to "pick & polish".

What is missing is a button to toggle into device emulation mode so I can see how my website looks on mobile screen sizes. Right now I have to copy/paste the link, open in my external browser and toggle emulation. Then when I find issues, paste screenshots back into the app.

I would prefer to be able to click the elements in the DOM using pick & polish to give the agent context.

### Proposed solution

Add this button like in Edge/other browsers to toggle between desktop/mobile emulation mode:

### Workflow impact

_No response_

### Installation context

_No response_

### Additional context

_No response_