feat(MiniCalendarWidget): enhance localization and refactor calendar logic

- Updated the MiniCalendarWidget to utilize localized strings for month names, weekdays, and loading messages, improving user experience across multiple languages.
- Refactored the calendar logic to use constants for month keys and weekday order, ensuring consistency with backend configurations.
- Added new translation entries for the mini widget in Cebuano, German, English, Spanish, and French, enhancing accessibility for users.

frontend/src/components/widgets/MiniCalendarWidget.vue

@@ -4,7 +4,7 @@
       {{ monthName }} {{ calendarData.year }}
     </div>
     <div class="mini-calendar-weekdays">
-      <span v-for="day in weekdays" :key="day" class="mini-calendar-weekday">{{ day }}</span>
+      <span v-for="day in weekdayLabels" :key="day" class="mini-calendar-weekday">{{ day }}</span>
     </div>
     <div class="mini-calendar-days">
       <span 
@@ -22,37 +22,36 @@
       </span>
     </div>
     <router-link to="/personal/calendar" class="mini-calendar-link">
-      Zum Kalender →
+      {{ $t('personal.calendar.miniWidget.linkToCalendar') }}
     </router-link>
   </div>
   <div v-else class="mini-calendar-empty">
-    Kalender wird geladen...
+    {{ $t('personal.calendar.miniWidget.loading') }}
   </div>
 </template>
 
 <script>
-const MONTH_NAMES = [
-  'Januar', 'Februar', 'März', 'April', 'Mai', 'Juni',
-  'Juli', 'August', 'September', 'Oktober', 'November', 'Dezember'
-];
+/** Order matches personal.calendar.months keys (jan … dec). */
+const CAL_MONTH_KEYS = ['jan', 'feb', 'mar', 'apr', 'may', 'jun', 'jul', 'aug', 'sep', 'oct', 'nov', 'dec'];
+/** Mon–Sun; matches backend firstDayOfWeek (Monday = 1). */
+const WEEKDAY_ORDER = ['mon', 'tue', 'wed', 'thu', 'fri', 'sat', 'sun'];
 
 export default {
   name: 'MiniCalendarWidget',
   props: {
     data: { type: Object, default: null }
   },
-  data() {
-    return {
-      weekdays: ['Mo', 'Di', 'Mi', 'Do', 'Fr', 'Sa', 'So']
-    };
-  },
   computed: {
     calendarData() {
       return this.data;
     },
     monthName() {
       if (!this.calendarData) return '';
-      return MONTH_NAMES[this.calendarData.month - 1];
+      const key = CAL_MONTH_KEYS[this.calendarData.month - 1];
+      return key ? this.$t(`personal.calendar.months.${key}`) : '';
+    },
+    weekdayLabels() {
+      return WEEKDAY_ORDER.map((k) => this.$t(`personal.calendar.weekdays.${k}`));
     },
     calendarDays() {
       if (!this.calendarData) return [];