[mdx] Add `<CH.Trace/>` component

[pomber]

Like in http://worrydream.com/#!/LearnableProgramming or https://www.replay.io/

Flow5.1.mp4

[texastoland]

Related:

• https://github.com/fullstackio/choc (same as video)
• https://github.com/ncase/joy (inspired by Logo)