Fix f-string syntax error with backslash in expression

app.py

@@ -128,10 +128,11 @@ export default GeneratedComponent;
 
             const sendMessage = () => {{
                 // postMessage for OpenPlatform integration
+                const safePrompt = '{prompt.replace("'", "\\'")}';
                 window.parent.postMessage({{
                     type: 'component-event',
                     data: {{ message, count }},
-                    prompt: '{prompt.replace("'", "\\'")}'
+                    prompt: safePrompt
                 }}, '*');
                 setCount(count + 1);
             }};