fix: resolve React Error #310 and refactor admin section

- Fix React bug #33580: remove Suspense boundaries co-located with Link components
- Delete settings/loading.tsx and admin/loading.tsx (root cause of race condition)
- Convert all admin navigation from Next.js Link to anchor tags
- Move admin pages to dedicated (admin) route group
- Add AdminHeader matching main header visual design
- Add AdminSidebar with anchor-based navigation
- Add /api/admin/models route handler (replaces server actions for GET)
- Add /api/debug/client-error for server-side browser error reporting
- Add useNoteRefreshOptional() to fix crash in AdminHeader
- Hide Admin Dashboard menu for non-admin users
- Change app icons from yellow to blue (#3A7CA5) matching brand primary
- Fix admin search bar width to match main header

Made-with: Cursor

memento-note/components/notification-panel.tsx

@@ -11,7 +11,7 @@ import {
 } from '@/components/ui/popover'
 import { getPendingShareRequests, respondToShareRequest } from '@/app/actions/notes'
 import { toast } from 'sonner'
-import { useNoteRefresh } from '@/context/NoteRefreshContext'
+import { useNoteRefreshOptional } from '@/context/NoteRefreshContext'
 import { cn } from '@/lib/utils'
 import { useLanguage } from '@/lib/i18n'
 
@@ -36,7 +36,7 @@ interface ShareRequest {
 }
 
 export function NotificationPanel() {
-  const { triggerRefresh } = useNoteRefresh()
+  const { triggerRefresh } = useNoteRefreshOptional()
   const { t } = useLanguage()
   const [requests, setRequests] = useState<ShareRequest[]>([])
   const [isLoading, setIsLoading] = useState(false)