Contribution guide

1. Add TSDoc to new public and internal callable units.
2. Keep Hono route path, validation, handler, and contract metadata together.
3. Run npm run docs:check before opening a pull request.
4. Inspect documentation/metadata/changes.json and report.json.
5. Review Cloudflare Pages preview before merge.

Existing undocumented symbols remain warnings through committed baseline. New undocumented symbols fail validation.