PhotoDotPi/pear-desktop ? reverse-engineered prompt

Build me a desktop app called Pear Desktop, a native feeling extension for a music player, with a clean Electron style window and a polished interface that works on macOS, Windows, and Linux.

I want it to feel like a proper desktop companion, not just a web page in a box. Include support for visual themes so users can change the look with CSS, and make it easy to add plugins that can tweak the app behavior and the page styling. The app should have a simple settings area for those visual tweaks and plugin options, plus a solid install and update friendly build that can be packaged for each platform.

Please make the project ready to run locally, easy to build, and include whatever basic tests and developer setup are needed. If you need to check current Electron or packaging docs while wiring things up, go ahead and look them up online.