Add maintenance management features: implement maintenance endpoints in the API, enhance media upload handling to skip duplicate files, and update frontend routes and translations for maintenance operations.

frontend/src/routes/admin.tsx

@@ -50,6 +50,13 @@ function AdminLayout() {
         >
           {t('admin.users.title')}
         </Link>
+        <Link
+          to="/admin/maintenance"
+          className={cn('pb-2 uppercase tracking-wide text-muted-foreground hover:text-foreground')}
+          activeProps={{ className: 'border-b-2 border-primary text-primary' }}
+        >
+          {t('admin.maintenance.title')}
+        </Link>
       </nav>
       <Outlet />
     </div>