hadetan/heygen-downloader ? reverse-engineered prompt

Build me a small desktop app that lets me download a public HeyGen video in one click.

I want to paste a HeyGen share URL, pick a folder on my computer, and hit Download. The app should open the share page, find the real downloadable mp4 behind it, and save it with a clean filename based on the page title. If the title is missing, use the video id instead. Show clear progress so I can tell when it is searching for the video and when it is actually downloading.

Please make it work on Windows and Mac, and keep the interface very simple with just the URL field, folder picker, and download button. Save my chosen download folder so it is remembered next time. If the link is private, broken, or there is no downloadable video, show a helpful error message. Look up current docs online if you need to.