Improve Theme Switching UX (Preview on Hover + Custom Themes)

Hey, just wanted to suggest a small UX improvement :slightly_smiling_face:

Right now changing themes in PC plantform takes a few clicks — you have to select one, then click “Apply” to see the effect. It would be great if themes could preview instantly (like on hover or select), so users can quickly compare them.

Also, it’d be cool to support custom themes in the future.

We’re testing some of this on our side — wondering if this is something the team would consider adding?

Thanks!