microsoft/microsoft-ui-XAML — reverse-engineered prompt

Build me a modern Windows UI framework like WinUI 3, with a clean Fluent Design feel and a set of polished controls and styles that app makers can use to build desktop Windows apps.

I want it to feel native on Windows, be fast, accessible, and work well on modern hardware. Include a small sample gallery app that shows the main controls in action, so someone can click around and see buttons, lists, navigation, text inputs, layouts, themes, and common app patterns. It should support building apps with C# or C++ where that makes sense, and target current Windows desktop app development through the Windows App SDK.

Please also add simple getting started docs, a basic roadmap style notes page, and clear contribution guidance. Keep the first version practical and buildable, not a giant Microsoft scale rewrite. Look up current Microsoft Learn docs online if you need to.