feat: add k8s cluster resource management module

- Add K8s module with kubeconfig storage in cluster_config table
- Implement resource list APIs for 8 kinds: namespace, deployment, statefulset, service, configmap, pod, pv, pvc
- Add K8sResourceList page with sidebar navigation and resource tables
- Support YAML upload/input dialog for resource creation via dynamic client
- Add kubeconfig settings drawer
- Increase main content width from lg to xl for better table display
- Add navigation link for cluster resources in top bar

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frontend/src/App.tsx

@@ -2,6 +2,7 @@ import { Container, Typography, Box, AppBar, Toolbar, Button, Stack } from '@mui
 import { Routes, Route, Link } from 'react-router-dom'
 import { useAppStore } from './stores/appStore'
 import RegistryImageList from './pages/RegistryImageList'
+import K8sResourceList from './pages/K8sResourceList'
 
 function App() {
   const { count, increment, decrement, reset } = useAppStore()
@@ -15,11 +16,13 @@ function App() {
           </Typography>
           <Button color="inherit" component={Link} to="/">首页</Button>
           <Button color="inherit" component={Link} to="/registry/image">镜像列表</Button>
+          <Button color="inherit" component={Link} to="/k8s/resources">集群资源</Button>
         </Toolbar>
       </AppBar>
-      <Container maxWidth="lg" sx={{ mt: 4, mb: 4 }}>
+      <Container maxWidth="xl" sx={{ mt: 4, mb: 4 }}>
         <Routes>
           <Route path="/registry/image" element={<RegistryImageList />} />
+          <Route path="/k8s/resources" element={<K8sResourceList />} />
           <Route path="/" element={
             <Box>
               <Typography variant="h4" component="h1" gutterBottom>