resolve issues with new features

frontend/src/pages/AdminDashboard.tsx

@@ -1,6 +1,6 @@
-import { useState } from 'react';
+import { useState, useEffect } from 'react';
 import { Box, Tabs, Tab, Typography } from '@mui/material';
-import { Navigate } from 'react-router-dom';
+import { Navigate, useSearchParams } from 'react-router-dom';
 import DashboardLayout from '../components/dashboard/DashboardLayout';
 import ServiceManagerTab from '../components/admin/ServiceManagerTab';
 import SystemHealthTab from '../components/admin/SystemHealthTab';
@@ -21,8 +21,19 @@ function TabPanel({ children, value, index }: TabPanelProps) {
   return <Box sx={{ pt: 3 }}>{children}</Box>;
 }
 
+const ADMIN_TAB_COUNT = 6;
+
 function AdminDashboard() {
-  const [tab, setTab] = useState(0);
+  const [searchParams] = useSearchParams();
+  const [tab, setTab] = useState(() => {
+    const t = Number(searchParams.get('tab'));
+    return t >= 0 && t < ADMIN_TAB_COUNT ? t : 0;
+  });
+
+  useEffect(() => {
+    const t = Number(searchParams.get('tab'));
+    if (t >= 0 && t < ADMIN_TAB_COUNT) setTab(t);
+  }, [searchParams]);
   const { user } = useAuth();
 
   const isAdmin = user?.groups?.includes('dashboard_admin') ?? false;