quiz seo image and authguard

components/quiz/quizzes-cta.tsx

@@ -6,7 +6,8 @@
  *   - "tile":   a card that leads the search page's "Start here" row.
  *   - "banner": a full-width row for the homepage, under sādhana / vāṇī.
  *
- * Renders nothing until there is at least one published quiz; with
+ * Signed-in readers only, like quizzes themselves. Renders nothing until
+ * there is at least one published quiz; with
  * `pendingOnly` it also hides once every quiz has been finished, so the
  * homepage only nudges when there's something left to do.
  */
@@ -28,9 +29,11 @@ export function QuizzesCTA({
   className?: string;
 }) {
   const { user } = useAuth();
+  const userId = user?.id;
   const [cards, setCards] = useState<QuizCard[] | null>(null);
 
   useEffect(() => {
+    if (!userId) return;
     let cancelled = false;
     quiz
       .list()
@@ -44,9 +47,10 @@ export function QuizzesCTA({
       cancelled = true;
     };
     // Refetch on sign-in/out: progress is per user.
-  }, [user?.id]);
+  }, [userId]);
 
-  if (!cards?.length) return null;
+  // Cards left over from before sign-out are ignored rather than cleared.
+  if (!user || !cards?.length) return null;
 
   if (pendingOnly && cards.every((c) => c.my.state === "completed")) {
     return null;