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

lib/date-keys.ts

@@ -0,0 +1,19 @@
+export function getTodayDateKey(date = new Date()) {
+  return date.toLocaleDateString("en-CA");
+}
+
+export function getNextLocalMidnight(from = new Date()) {
+  return new Date(
+    from.getFullYear(),
+    from.getMonth(),
+    from.getDate() + 1,
+    0,
+    0,
+    0,
+    0,
+  );
+}
+
+export function getMillisecondsUntilLocalMidnight(from = new Date()) {
+  return Math.max(0, getNextLocalMidnight(from).getTime() - from.getTime());
+}