added demo quiz reset option. Added timer for next available daily quiz

components/daily-quiz/daily-quiz-countdown.tsx

@@ -0,0 +1,67 @@
+"use client";
+
+import { useEffect, useRef, useState } from "react";
+
+import {
+  formatDailyQuizCountdown,
+  getMillisecondsUntilNextDailyQuiz,
+  getNextDailyQuizAvailableAt,
+} from "@/lib/daily-quiz-storage";
+
+type DailyQuizCountdownProps = {
+  onAvailable?: () => void;
+};
+
+export function DailyQuizCountdown({ onAvailable }: DailyQuizCountdownProps) {
+  const [remainingMs, setRemainingMs] = useState(() =>
+    getMillisecondsUntilNextDailyQuiz(),
+  );
+  const hasNotifiedRef = useRef(false);
+
+  useEffect(() => {
+    const tick = () => {
+      const nextRemainingMs = getMillisecondsUntilNextDailyQuiz();
+      setRemainingMs(nextRemainingMs);
+
+      if (nextRemainingMs === 0) {
+        if (!hasNotifiedRef.current) {
+          hasNotifiedRef.current = true;
+          onAvailable?.();
+        }
+        return;
+      }
+
+      hasNotifiedRef.current = false;
+    };
+
+    tick();
+    const intervalId = window.setInterval(tick, 1000);
+
+    return () => {
+      window.clearInterval(intervalId);
+    };
+  }, [onAvailable]);
+
+  const nextAvailableAt = getNextDailyQuizAvailableAt();
+  const nextAvailableLabel = nextAvailableAt.toLocaleString(undefined, {
+    weekday: "short",
+    month: "short",
+    day: "numeric",
+    hour: "numeric",
+    minute: "2-digit",
+  });
+
+  return (
+    <div className="space-y-1 pt-1">
+      <p className="text-sm text-muted-foreground">
+        Next check-in available in{" "}
+        <span className="font-medium tabular-nums text-foreground">
+          {formatDailyQuizCountdown(remainingMs)}
+        </span>
+      </p>
+      <p className="text-xs text-muted-foreground">
+        Opens at midnight ({nextAvailableLabel})
+      </p>
+    </div>
+  );
+}