filecxx/FileCentipede ? reverse-engineered prompt

Build me a cross platform download manager app that feels fast and easy to use, with a clean desktop interface and browser integration.

I want it to handle regular file downloads over HTTP and HTTPS, plus FTP, SFTP, WebDAV, magnet links, torrents, m3u8 streams, and direct video or audio grabbing from websites. It should let me pause, resume, queue, limit speed, manage proxies, and organize downloads into folders. I also want built in tools for things like merging files, checking checksums, encoding and decoding links, and making or converting torrents and magnets.

Please include support for browsing remote files on FTP, SSH, and WebDAV servers, and make it possible to upload files and folders too. The app should feel polished, support multiple languages, and work well with browser extensions so it can capture media and links from web pages. If you need to look up current docs online for any libraries or integrations, go ahead.