imsyy/yt-dlp-gui ? reverse-engineered prompt

Build me a modern desktop app for downloading videos with yt dlp, something that feels simple enough that I can just paste a link and go.

I want a clean cross platform app for Windows, Mac, and Linux, with a nice dark and light interface, and support for English plus a few other languages. The main screen should let me paste a video URL, instantly show the title, thumbnail, length, and available download options, then let me choose video only, audio only, or a full video download. It should also handle playlists, show download progress clearly, and let me pause, resume, or cancel jobs.

Please include a few useful extras like subtitle downloading, thumbnail saving, trimming to a time range, custom file naming, and an easy way to use cookies for private or age restricted videos. If it makes sense, add a small browser helper so I can send the current page straight into the app without copying links around.