Azulzzxd/Velocity-User-Interface ? reverse-engineered prompt

Build me the Velocity user interface as a polished C# desktop app that matches the look and feel shown in the screenshots and README.

I want a modern launcher style interface with a sidebar, a title bar that feels like WinUI, custom message boxes, notifications, a theme menu, accent colors, and a changelog page. Please also include the client manager with an option to hide it, multi instance support, injector checks, an antivirus detector, and support for animated GIFs in the media overlay.

Make it feel like a real product, not just a mockup, with the main screens connected and working smoothly. Keep the code clean and well commented since this project is supposed to be the full source for the current UI. If you need to check the latest docs for any UI components or Windows features, go ahead and look them up online.