Fix tool feedback survey (#945)

fix(tool-feedback): guard setSurveyData with mounted ref instead of unsubscribing

Unsubscribing posthog.onFeatureFlags on cleanup removed the handler
before it could fire, leaving surveyData null and the page stuck at
"Loading...". Keep the handler registered (so it fires when flags
load) and gate the setState call on a mounted flag to avoid stale
updates after unmount.

Author: EricGustin

app/_components/tool-feedback-survey.tsx

@@ -11,15 +11,21 @@ export const ToolFeedbackSurvey = () => {
   const [completed, setCompleted] = useState(false);
 
   useEffect(() => {
-    const unsubscribe = posthog.onFeatureFlags(() => {
+    let mounted = true;
+    posthog.onFeatureFlags(() => {
       posthog.getSurveys((surveys) => {
+        if (!mounted) {
+          return;
+        }
         const survey = surveys.find((s) => s.id === SURVEY_ID);
         if (survey) {
           setSurveyData(survey);
         }
       }, true);
     });
-    return unsubscribe;
+    return () => {
+      mounted = false;
+    };
   }, []);
 
   const handleSurveyComplete = () => {