Blinue/Magpie ? reverse-engineered prompt

Build me a lightweight Windows app that helps me upscale a game or other window without going fullscreen. I want to be able to pick a window, choose an upscaling mode, and have it work for both windowed and fullscreen use cases. Please include a clean modern interface with light and dark themes, support for multiple monitors, and a few built in scaling options like Anime4K, FSR, and some shader style filters such as CRT.

It should feel simple to use, with a main screen for selecting the target window and settings, plus clear status so I can tell when scaling is active. Make it work on Windows 10 and 11, and keep it efficient so it does not feel heavy. If you need to, look up any current docs or best practices online while you build it.