cubiclesoft/js-fileexplorer ? reverse-engineered prompt

Build me a clean, mobile friendly file explorer widget for the browser that can show folders and files, let me select items, rename them, move or copy them, delete them, upload files and folders, and download files or whole folders.

I want it to feel like a real file manager, with a toolbar, right click actions, keyboard shortcuts, drag and drop, and support for both mouse and touch. It should work with large folders without getting slow, and it should show thumbnails when available. Make it customizable enough that I can hook it up to my own backend later, since the browser side is the main part here.

Please keep it dependency free, use plain JavaScript, and make sure it looks good on desktop and mobile. If you need to check anything, look up the current docs online.