* Migrate to ESM and upgrade dependencies
* Address review: use type-only import for QualityOptions
* update version to 6.0.0 in package.json and package-lock.json
* Add ESM migration note to README for V6
* Update test imports for ESM and clean up devDependencies (ts-node, @types/jest)
* Pin @types/node to 24.x and refine tsconfig/README wording