agalwood/motrix ? reverse-engineered prompt

Build me a modern download manager called Motrix that feels clean and simple, but still supports all the things people actually use, like HTTP, FTP, magnet links, and BitTorrent downloads. I want a desktop app for Mac, Windows, and Linux, with dark mode, a dashboard that shows transfer stats and active downloads, and a detailed downloads view where I can pause, resume, limit speed, and see progress clearly.

Please also include support for browser handoff from Chrome and Firefox, a tray icon, notifications when downloads finish, and file associations for magnet and torrent files. If it makes sense, add a headless mode too, so it can run on a server or in Docker and be controlled remotely with a simple command line tool or web interface. Use current docs online if you need to. Keep the experience polished and easy to use, and make sure downloads restore after restart.