feat: K8s节点管理+工作负载独立组件，架构拓扑可拖拽编辑

- 新建 K8sNodes.tsx: 集群选择→节点表格(角色/状态/CPU/Mem/Pods/Kubelet版本)
- 新建 K8sWorkloads.tsx: Deployment+Pod双Tab，副本/镜像/重启次数/状态
- TopologyView: SVG节点支持鼠标拖拽，实时更新坐标，cursor grab/grabbing
- 节点/工作负载路由从K8sClusters占位改为独立组件
- Sidebar: Kubernetes管理→Kubernetes

frontend/src/App.tsx

@@ -13,6 +13,8 @@ import { RegionManager } from '@/components/cloud/RegionManager';
 import { PlatformManager } from '@/components/cloud/PlatformManager';
 import { CloudBilling } from '@/components/cloud/CloudBilling';
 import { K8sClusters } from '@/components/k8s/K8sClusters';
+import { K8sNodes } from '@/components/k8s/K8sNodes';
+import { K8sWorkloads } from '@/components/k8s/K8sWorkloads';
 import { TopologyView } from '@/components/k8s/TopologyView';
 import { AlertManager } from '@/components/monitor/AlertManager';
 import { AppReleaseManager } from '@/components/deploy/AppRelease';
@@ -59,8 +61,8 @@ function App() {
             <Route path="cloud-billing" element={<CloudBilling />} />
             <Route path="agent-monitor" element={<AgentMonitor />} />
             <Route path="clusters" element={<K8sClusters />} />
-            <Route path="nodes" element={<K8sClusters />} />
-            <Route path="workloads" element={<K8sClusters />} />
+            <Route path="nodes" element={<K8sNodes />} />
+            <Route path="workloads" element={<K8sWorkloads />} />
             <Route path="topology" element={<TopologyView />} />
             {/* 应用发布 */}
             <Route path="pipelines" element={<PipelineManager />} />