Fix stale contributor docs (Yarn 4, main branch, package scopes) #194

Priority: P2

Context

Agents trust the docs, and docs/development.md is out of date: it says to install Yarn Classic while the repo pins Yarn 4.1.0, it links a master branch that doesn't exist, and its scopes table leaves out two of the four packages.

Do

• docs/development.md:7: replace "Latest Yarn Classic" with corepack enable (Yarn 4).
• :8: link .../blob/main/.nvmrc instead of master.
• :48: add dom (@assertive-ts/dom) and native (@assertive-ts/native) to the scopes table.
• Link to the agent instruction file once Add an agent instruction file (AGENTS.md + CLAUDE.md) #190 is merged.
• Commit as docs(all): update development guide for Yarn 4 and all package scopes.

Done when

Following the doc step by step on a clean clone ends in a green yarn check.

Source: code audit of stackbuilders/assertive-ts at e81a614 (2026-10-13) plus open Vanta/Dependabot findings.