Port from TypeScript

A construct mapping and two boundaries, nothing else

This skill maps the JavaScript runtime to Rust and owns the two boundaries, napi-rs and wasm-bindgen. The parity contract, the phases, and the anti-patterns are /port-to-rust. TypeScript and JavaScript are one skill because they are one runtime: the types are erased before anything runs, so the mapping is the same and the annotations are evidence about intent, not guarantees about values.

The end state decides whether a binding layer appears at all

/port-to-rust names three end states, and this skill asks rather than assumes.