AmbientRun/Ambient ? reverse-engineered prompt

Build me a cross platform multiplayer game engine and runtime that lets people make and share 3D games on the web and desktop. I want the core to support a simple real time entity system, automatic syncing between players, packaged game logic that can run safely in WebAssembly, and a smooth 3D renderer with modern lighting and assets. It should also include a small example game or demo so someone can open it and see multiplayer working right away.

Please make it feel like a real product, with a clear way to run it locally, build it for the web, and extend it with game code and assets. If you need current docs or APIs, look them up online and follow the latest guidance.