feat(k8s): M2 Pod Metrics 详情页接入 — ListPods 注入 metrics

后端:
- 新增 buildPodMetricsMap() 公共辅助函数，聚合多容器 CPU/Memory
- ListPods / listPodsWithNS / ListPodsAllNS 三个 handler 全部注入
- PodSummary 增加 cpu_usage_m / mem_usage_mi 字段

前端:
- KubernetesWorkloads Pod 表格增加 CPU/内存列
- NamespaceResourcePage Pod 表格增加 CPU/内存列

验证:
- 17 个 Pod 全部返回真实 metrics (argocd/demo-jar)
- curl /kubernetes-clusters/1/pods → cpu_usage_m='2m' mem_usage_mi='61Mi'

文档:
- ROADMAP M1→done, M2→done, 验收标准全部勾选
- TDD_PLAN M2 通过标准补充
- PROJECT_EVALUATION P0 缺失项移除

frontend/src/components/kubernetes/KubernetesWorkloads.tsx

@@ -275,15 +275,17 @@ export function KubernetesWorkloads() {
                     <TableHead className="text-slate-400">命名空间</TableHead>
                     <TableHead className="text-slate-400">状态</TableHead>
                     <TableHead className="text-slate-400">节点</TableHead>
+                    <TableHead className="text-slate-400">CPU</TableHead>
+                    <TableHead className="text-slate-400">内存</TableHead>
                     <TableHead className="text-slate-400">重启</TableHead>
                     <TableHead className="text-slate-400">镜像</TableHead>
                   </TableRow>
                 </TableHeader>
                 <TableBody>
                   {loading ? (
-                    <TableRow><TableCell colSpan={6} className="text-center text-slate-500 py-12"><Loader2 className="h-5 w-5 animate-spin mx-auto mb-2" />加载中...</TableCell></TableRow>
+                    <TableRow><TableCell colSpan={8} className="text-center text-slate-500 py-12"><Loader2 className="h-5 w-5 animate-spin mx-auto mb-2" />加载中...</TableCell></TableRow>
                   ) : filteredPods.length === 0 ? (
-                    <TableRow><TableCell colSpan={6} className="text-center text-slate-500 py-12"><Container className="h-8 w-8 mx-auto mb-2 opacity-50" />暂无 Pod</TableCell></TableRow>
+                    <TableRow><TableCell colSpan={8} className="text-center text-slate-500 py-12"><Container className="h-8 w-8 mx-auto mb-2 opacity-50" />暂无 Pod</TableCell></TableRow>
                   ) : (
                     filteredPods.map((p) => (
                       <TableRow key={p.id} className="border-slate-800 hover:bg-slate-800/30">
@@ -291,6 +293,8 @@ export function KubernetesWorkloads() {
                         <TableCell><Badge variant="outline" className="border-slate-700 text-slate-400">{p.namespace}</Badge></TableCell>
                         <TableCell>{getPodStatusBadge(p.status)}</TableCell>
                         <TableCell className="text-sm text-slate-400">{p.node_name || '-'}</TableCell>
+                        <TableCell className="text-sm text-cyan-400">{p.cpu_usage_m || '-'}</TableCell>
+                        <TableCell className="text-sm text-amber-400">{p.mem_usage_mi || '-'}</TableCell>
                         <TableCell className={p.restart_count > 0 ? 'text-yellow-400' : 'text-slate-500'}>{p.restart_count || 0}</TableCell>
                         <TableCell className="text-xs text-slate-500 max-w-[200px] truncate">{p.image || '-'}</TableCell>
                       </TableRow>