resolve issues with new features

frontend/src/components/shared/Sidebar.tsx

@@ -20,8 +20,7 @@ import {
   CalendarMonth,
   MenuBook,
   AdminPanelSettings,
-  ChevronLeft,
-  ChevronRight,
+  Menu as MenuIcon,
 } from '@mui/icons-material';
 import { useNavigate, useLocation } from 'react-router-dom';
 import { useLayout, DRAWER_WIDTH, DRAWER_WIDTH_COLLAPSED } from '../../contexts/LayoutContext';
@@ -104,6 +103,11 @@ function Sidebar({ mobileOpen, onMobileClose }: SidebarProps) {
   const drawerContent = (
     <Box sx={{ display: 'flex', flexDirection: 'column', height: '100%' }}>
       <Toolbar />
+      <Box sx={{ display: 'flex', justifyContent: sidebarCollapsed ? 'center' : 'flex-end', px: 1, py: 0.5 }}>
+        <IconButton onClick={toggleSidebar} aria-label="Sidebar umschalten">
+          <MenuIcon />
+        </IconButton>
+      </Box>
       <List sx={{ flex: 1 }}>
         {navigationItems.map((item) => {
           const isActive = location.pathname === item.path;
@@ -154,11 +158,6 @@ function Sidebar({ mobileOpen, onMobileClose }: SidebarProps) {
           );
         })}
       </List>
-      <Box sx={{ display: 'flex', justifyContent: 'center', mb: 1 }}>
-        <IconButton onClick={toggleSidebar} aria-label="Sidebar umschalten">
-          {sidebarCollapsed ? <ChevronRight /> : <ChevronLeft />}
-        </IconButton>
-      </Box>
     </Box>
   );