Static type checks

[andrewkmin]

Would be nice to have static type + lint checks, to verify validity of logic pre-runtime

[r-n-o]

I think more realistically we should move to TypeScript and add a compilation step. The initial "vision" for this repo was to minimize the amount of tooling and dependencies we rely on, such that people loading iframes can understand where the code comes from with minimal hops. I think a ts->js compilation step would get us a lot of safety and comfort for a minimal number of extra hops: one. Typescript as a dependency is also safe to take, as long as the compiled code is checked in and reviewed.

We could mirror the setup of https://github.com/paulmillr/noble-curves to get there.