Optimize auth initialization by using cached middleware state

- Replace API calls with cached auth state from middleware in useAuthorization
- Add fallback to session cache and watchers for auth state updates
- Change initialization from async to synchronous for better performance
- Add DuplicateNotificationBanner component

pages/dashboard.vue

@@ -8,7 +8,7 @@
 
       <v-list color="primary" lines="two">
         <v-list-item
-          v-for="(item, index) in menu"
+          v-for="(item, index) in safeMenu"
           :key="index"
           :to="item.to"
           :title="item.title"
@@ -191,6 +191,53 @@ const menu = computed(() =>
   toValue(tags).interest ? interestMenu : defaultMenu
 );
 
+// Safe menu wrapper to prevent crashes when menu is undefined
+const safeMenu = computed(() => {
+  try {
+    const currentMenu = menu.value;
+    if (Array.isArray(currentMenu)) {
+      return currentMenu;
+    }
+    
+    console.warn('[Dashboard] Menu is not an array, returning fallback menu');
+    
+    // Fallback menu with essential items (including admin for safety)
+    return [
+      {
+        to: "/dashboard/interest-list",
+        icon: "mdi-view-list",
+        title: "Interest List",
+      },
+      {
+        to: "/dashboard/expenses",
+        icon: "mdi-receipt",
+        title: "Expenses",
+      },
+      {
+        to: "/dashboard/file-browser",
+        icon: "mdi-folder",
+        title: "File Browser",
+      },
+      {
+        to: "/dashboard/admin",
+        icon: "mdi-shield-crown",
+        title: "Admin Console",
+      },
+    ];
+  } catch (error) {
+    console.error('[Dashboard] Error computing menu:', error);
+    
+    // Emergency fallback menu
+    return [
+      {
+        to: "/dashboard/interest-list",
+        icon: "mdi-view-list",
+        title: "Interest List",
+      },
+    ];
+  }
+});
+
 const logOut = async () => {
   await logout();
   return navigateTo("/login");

pages/dashboard/interest-list.vue

@@ -1,6 +1,9 @@
 <template>
   <div>
     <v-container fluid>
+      <!-- Duplicate notification banner for admins -->
+      <DuplicateNotificationBanner />
+      
       <!-- Header Section -->
       <v-row class="mb-4 mb-md-6">
         <v-col cols="12" md="8">