Fix live test follow-up issues

src/lib/date-utils.ts

@@ -46,3 +46,7 @@ export function getWorkingDaysOfMonth(year: number, month: number) {
     .filter((day) => !isWeekend(day))
     .map((day) => startOfDay(day));
 }
+
+export function formatDateKey(date: Date) {
+  return format(date, "yyyy-MM-dd");
+}