yuvrajlaptop2008-byte/Mate-Engine ? reverse-engineered prompt

Build me a lightweight desktop pet app like Desktop Mate, but free and open source, with support for custom VRM avatars and modding.

I want the avatar to sit on the desktop, window edges, and taskbar, react when I drag it around, idle on its own, dance, and show cute messages for different actions. Please include a simple settings menu I can open with a right click or a key press, plus options like always on top, FPS control, and basic animation and appearance settings.

It should feel smooth and polished, work well on low memory, and support extra features like custom shaders, multiple avatars if possible, and a system tray icon. Make it easy to swap models and keep the app organized so it can be expanded later. If you need current docs or references for any Unity or VRM details, look them up online first.