Add comprehensive OpenAPI/Swagger API documentation

- Install swagger-ui-express and swagger-jsdoc dependencies
- Create comprehensive OpenAPI 3.0 specification with detailed schemas
- Add interactive Swagger UI at /api-docs endpoint
- Document all public API endpoints (/api/config, /api/locations)
- Document admin authentication and management endpoints
- Include comprehensive request/response schemas and examples
- Add authentication documentation for admin endpoints
- Update CLAUDE.md with API documentation information

Features:
- Complete API specification with OpenAPI 3.0 standard
- Interactive documentation interface with Swagger UI
- Detailed request/response examples for all endpoints
- Authentication flows for admin functionality
- Error response documentation with examples
- Type-safe integration with existing TypeScript architecture

API Documentation available at: /api-docs

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

CLAUDE.md

@@ -21,6 +21,17 @@ npm run dev-with-css     # Legacy JS + CSS watching
 
 The application runs on port 3000 by default. Visit http://localhost:3000 to view the website.
 
+### API Documentation
+Interactive OpenAPI/Swagger documentation is available at `/api-docs` when the server is running:
+- **Development**: http://localhost:3000/api-docs
+- **Production**: https://yourapp.com/api-docs
+
+The documentation includes:
+- Complete API endpoint specifications
+- Request/response schemas and examples
+- Authentication requirements
+- Interactive testing interface
+
 ### TypeScript Development
 The backend is written in TypeScript and compiles to `dist/` directory.
 ```bash