- Add OpenAPI 3.0 spec (OPENAPI_SPEC) describing all API endpoints
- Add /swagger page with Swagger UI loaded from CDN (unpkg.com)
- Add /api/openapi.json endpoint serving the spec
- Add "API docs" link on the main page
- Use ThreadingHTTPServer for concurrent requests
- Document Swagger UI in route-web-api.md
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>