Add event management system with calendar and CRUD operations

- Add EventCalendar component with FullCalendar integration
- Create event CRUD dialogs and upcoming event banner
- Implement server-side events API and database utilities
- Add events dashboard page and navigation
- Improve dues calculation with better overdue day logic
- Install FullCalendar and date-fns dependencies

layouts/dashboard.vue

@@ -25,6 +25,13 @@
           title="Dashboard"
           value="dashboard"
         />
+
+        <v-list-item 
+          to="/dashboard/events" 
+          prepend-icon="mdi-calendar"
+          title="Events"
+          value="events"
+        />
         
         <v-list-item 
           to="/dashboard/user"