MCbabel/Steam-Manifest-Downloader — reverse-engineered prompt

Build me a clean desktop app for Windows and Linux that helps me download Steam depots from manifest data in a simple way. I want to be able to drag and drop a .lua file, or search for a game, then see the available depots and manifests, pick what I want, and hit one download button. The app should automatically handle manifest lookup, fetch anything it needs from archive sources, generate depot keys, run the embedded downloader in the background, and show real time progress so I can tell what is happening.

Please make it feel polished, with dark and light theme support, game names and cover art from the Steam store, and a settings area for download location and an optional GitHub token. Keep it self contained as much as possible and make the flow friendly for non technical users. Include sensible warnings that this is only for legally owned content, not piracy. If you need details, look up current docs online and wire everything together end to end.