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

Build me a desktop app called Xtream Portal Checker that lets me paste or load Xtream Codes portal lines, clean them up, and check the playlists one by one or all at once.

After a line is checked, I want to be able to open it, browse the available streams, and play them inside the app. It should also support a favourites list, show EPG data when it exists, and let me switch between dark mode and light mode. Please make it feel simple and polished for someone who just wants to paste in their lines, verify what works, and start watching.

If anything about the format or stream access needs current info, look it up online and make sensible choices. Keep it working smoothly, with clear feedback when a portal line fails or succeeds, and do not include any playlist content in the app itself.