Hardhat V3 Migration Validator

Post-migration correctness validator for Hardhat V2 → V3 migrations. Version 0.1.1 answers whether a Hardhat repo is actually V3-ready, not just migrated. Single-file, zero-dependency Node.js CLI (Node 18+). Checks dependency surfaces, CJS/ESM mismatches, config shapes, plugin ecosystem upgrades, and ethers v5 remnants. Complements Nomic Foundation's migration skill effort. Runs in under 5 seconds on large monorepos, never mutates the repo, and produces both JSON and Markdown reports with a five-level severity model (BLOCKER, HIGH, MEDIUM, LOW, INFO). Designed for Hardhat developers completing V2→V3 migration.