liabru/matter-js ? reverse-engineered prompt

Build me a JavaScript 2D physics engine for the web that people can drop into a page and use to make simple games and interactive demos.

I want bodies that fall, bounce, stack, slide, and collide naturally, plus support for circles, rectangles, polygons, compound shapes, constraints, gravity, friction, sleeping, and events. It should also have a basic canvas renderer so I can see the simulation running right away, and a handful of demo scenes like stacks, bridges, a slingshot, a car, soft bodies, cloth, raycasting, and collision filtering.

Please make it work nicely in the browser, keep it usable from Node too, and include a clean example or two that shows how to create a world and step the simulation. If you need to look up current docs online, go ahead and do that.