feat(ux): U1 虚拟滚动 — Pod/事件/审计/命令列表大数据量渲染优化

- 安装 @tanstack/react-virtual@3.14.4
- 新增 hooks/useVirtualRows.ts 可复用虚拟滚动 Hook
- PodsTab: 全量渲染→虚拟滚动, 支持 1000+ Pod + 动态行高(展开行)
- EventTable: 移除 maxRows=200 截断, 万级事件流畅渲染
- AuditOperationsTab: shadcn Table→虚拟滚动 CSS Grid 布局
- SessionCommandsPanel: 虚拟滚动, page_size 200→500
- npm run build ✅, tsc --noEmit ✅, 17/17 集成测试通过

frontend/package.json

@@ -43,6 +43,7 @@
     "@radix-ui/react-tooltip": "^1.2.8",
     "@tanstack/react-query": "^5.95.2",
     "@tanstack/react-query-devtools": "^5.95.2",
+    "@tanstack/react-virtual": "^3.14.4",
     "@types/react-router-dom": "^5.3.3",
     "@uiw/react-codemirror": "^4.25.10",
     "class-variance-authority": "^0.7.1",