fix: update DateMonthYearPicker formatter to use currentMonthYear

frontend/src/pages/Calendar.vue

@@ -39,6 +39,7 @@
     >
       <template
         #header="{
+          currentMonthYear,
           enabledModes,
           activeView,
           selectedMonthDate,
@@ -55,7 +56,7 @@
           <div class="flex items-center">
             <DateMonthYearPicker
               :modelValue="selectedMonthDate"
-              :formatter="(d) => dayjs(d).format('MMM YYYY')"
+              :formatter="() => currentMonthYear"
               @update:modelValue="(val) => onMonthYearChange(val)"
             />
           </div>