docs(hono): clarify CORS middleware must be registered before routes (#3707)

- Add complete example showing app.on() and serve() after CORS setup
- Include important note explaining CORS must come before route registration
- Ensures consistency with middleware section and prevents user confusion
- Critical for proper cross-origin request handling in authentication endpoints

docs/content/docs/integrations/hono.mdx

@@ -48,8 +48,14 @@ app.use(
 	}),
 );
 
+app.on(["POST", "GET"], "/api/auth/*", (c) => {
+	return auth.handler(c.req.raw);
+});
+
+serve(app);
 ```
 
+> **Important:** CORS middleware must be registered before your routes. This ensures that cross-origin requests are properly handled before they reach your authentication endpoints.
 
 ### Middleware