resolve issues with new features

frontend/src/components/shared/Sidebar.tsx

@@ -20,6 +20,7 @@ import {
   CalendarMonth,
   MenuBook,
   AdminPanelSettings,
+  Settings,
   Menu as MenuIcon,
 } from '@mui/icons-material';
 import { useNavigate, useLocation } from 'react-router-dom';
@@ -78,6 +79,12 @@ const adminItem: NavigationItem = {
   path: '/admin',
 };
 
+const adminSettingsItem: NavigationItem = {
+  text: 'Einstellungen',
+  icon: <Settings />,
+  path: '/admin/settings',
+};
+
 interface SidebarProps {
   mobileOpen: boolean;
   onMobileClose: () => void;
@@ -92,7 +99,7 @@ function Sidebar({ mobileOpen, onMobileClose }: SidebarProps) {
   const isAdmin = user?.groups?.includes('dashboard_admin') ?? false;
 
   const navigationItems = useMemo(() => {
-    return isAdmin ? [...baseNavigationItems, adminItem] : baseNavigationItems;
+    return isAdmin ? [...baseNavigationItems, adminItem, adminSettingsItem] : baseNavigationItems;
   }, [isAdmin]);
 
   const handleNavigation = (path: string) => {