kiddac/Stalker-Portal-Checker ? reverse-engineered prompt

Build me a simple desktop app for checking Stalker portal lines and playing streams.

I want to paste in or load my stb stalker lines, then have the app clean them up and show the cleaned list in a separate area. From there I should be able to open a playlists screen, check one line at a time or check all of them in one go, and once a line is verified I can view that line and play whatever streams are available.

Please make it feel like a real player too, with a favorites list, support for channel EPG where data exists, and an easy dark mode and light mode switch. It should also support multiple languages. Keep it simple and usable, since this is meant to be a checker and a basic player, not a full IPTV service. If you need to look up current docs or best practices for any playback or UI parts, go ahead and do that.