chore: release 0.1.2 metadata + adoption README

[greyllmmoder]

Summary

• strengthen npm metadata (description, repository, bugs, homepage, keywords)
• rewrite README for clearer value proposition and CI-first onboarding
• bump version to 0.1.2 and publish to npm

Testing

• npm run typecheck
• npm run build
• npm test
• npm run dev -- check --pattern "examples/**/*.ts" (expected non-zero because drift exists in demo)

Publish

• npm publish --access public
• published: zodrift@0.1.2