solidjs/solid ? reverse-engineered prompt

Build me a fast, modern JavaScript UI library like SolidJS, with a simple reactive model where components are just functions and state updates only the parts of the page that depend on them.

I want it to support JSX, fragments, context, portals, suspense, error boundaries, and both client rendering and server rendering. Make the basic developer experience feel clean and easy, with a small counter example, a good starter app, and enough docs or examples to show how to use signals, derived values, and rendering. If you need to check the latest docs or best practices online, do that.

Please set it up as a polished TypeScript project with a solid package structure, tests, and the usual tooling so it feels like a real open source library I could publish and work on over time.