refactor: Migrate frontend to use Vite and update testing framework

### Summary of Changes
- Replaced `react-query` with `@tanstack/react-query` in `package.json` and updated related imports.
- Updated frontend CI workflow to use `vitest` for testing instead of Jest, modifying test commands accordingly.
- Removed the `App.js`, `Dashboard.js`, `Settings.js`, and other component files, transitioning to a new structure.
- Enhanced error handling in the `useServiceStatus` hook to provide more informative error messages.

### Expected Results
- Improved performance and modernized the frontend build process with Vite.
- Streamlined testing setup with `vitest`, enhancing test execution speed and reliability.
- Increased clarity and maintainability of the codebase by adhering to clean code principles and removing unused components.

frontend/src/App.jsx

@@ -0,0 +1,78 @@
+import React from 'react';
+import { Routes, Route } from 'react-router-dom';
+import { Layout, Menu, Typography } from 'antd';
+import { DashboardOutlined, SettingOutlined, BarChartOutlined } from '@ant-design/icons';
+import Dashboard from './components/Dashboard.jsx';
+import SystemMetrics from './components/SystemMetrics.jsx';
+import Settings from './components/Settings.jsx';
+import OfflineMode from './components/OfflineMode.jsx';
+import ErrorBoundary from './components/common/ErrorBoundary.jsx';
+import { useServiceStatus } from './hooks/useServiceStatus';
+import './App.css';
+
+const { Header, Sider, Content } = Layout;
+const { Title } = Typography;
+
+function App() {
+  const serviceStatus = useServiceStatus();
+
+  const handleRetry = () => {
+    window.location.reload();
+  };
+
+  return (
+    <ErrorBoundary>
+      <Layout style={{ minHeight: '100vh' }}>
+        <Sider width={250} theme="dark">
+          <div style={{ padding: '16px', textAlign: 'center' }}>
+            <Title level={3} style={{ color: 'white', margin: 0 }}>
+              LabFusion
+            </Title>
+          </div>
+          <Menu
+            theme="dark"
+            mode="inline"
+            defaultSelectedKeys={['dashboard']}
+            items={[
+              {
+                key: 'dashboard',
+                icon: <DashboardOutlined />,
+                label: 'Dashboard',
+              },
+              {
+                key: 'metrics',
+                icon: <BarChartOutlined />,
+                label: 'System Metrics',
+              },
+              {
+                key: 'settings',
+                icon: <SettingOutlined />,
+                label: 'Settings',
+              },
+            ]}
+          />
+        </Sider>
+        <Layout>
+          <Header style={{ background: '#fff', padding: '0 24px', boxShadow: '0 2px 8px rgba(0,0,0,0.1)' }}>
+            <Title level={4} style={{ margin: 0, lineHeight: '64px' }}>
+              Homelab Dashboard
+            </Title>
+          </Header>
+          <Content style={{ margin: '24px', background: '#fff', borderRadius: '8px' }}>
+            {serviceStatus.overall === 'offline' && (
+              <OfflineMode onRetry={handleRetry} />
+            )}
+            <Routes>
+              <Route path="/" element={<Dashboard />} />
+              <Route path="/dashboard" element={<Dashboard />} />
+              <Route path="/metrics" element={<SystemMetrics />} />
+              <Route path="/settings" element={<Settings />} />
+            </Routes>
+          </Content>
+        </Layout>
+      </Layout>
+    </ErrorBoundary>
+  );
+}
+
+export default App;