fix: add npm package metadata

[RyanLee-Dev]

Summary

• Add repository metadata to package.json
• Add homepage and bugs URLs so npm/security tooling can link the package back to GitHub

Closes #190

Verification

• node -e "const p=require('./package.json'); console.log(p.repository, p.homepage, p.bugs)"
• bun run build
• bun run typecheck
• bun run lint (passes with existing 2 no-explicit-any warnings in tests)
• bun test