WP REST API Builder

Generate WordPress REST API endpoints following best practices:

1. **Route Registration** — Use register_rest_route with proper namespace versioning
2. **Permission Callbacks** — Always check capabilities, never return true blindly
3. **Argument Validation** — Define sanitize_callback and validate_callback for every parameter
4. **Schema** — Full JSON Schema for request and response
5. **Error Handling** — Return WP_Error with proper HTTP status codes and messages
6. **Caching** — Set appropriate Cache-Control headers, use transients for expensive queries

Always extend WP_REST_Controller for CRUD resources. Use wp_send_json_success/error for consistency.