feat: 重构监控中心导航，新增资源监控4大模块

- 主菜单「监控告警」→「监控中心」
- 「告警中心」→「告警服务」移至链路追踪下方
- 新增资源监控 Tab 页（主机/中间件/SNMP/站点拨测）
- Agent 新增网络采集器(network)和磁盘IO采集器(diskio)
- 后端扩展 Agent 上报模型，支持 NetworkStat/DiskIOStat
- 前端 ServerTableRow 展示网络和磁盘IO实时指标
- WebSocket MetricsUpdate 推送扩展

frontend/src/components/layout/Sidebar.tsx

@@ -59,7 +59,6 @@ const menuItems: MenuItem[] = [
       { id: 'regions', name: '区域管理', icon: MapPin, path: '/regions' },
       { id: 'platforms', name: '云平台', icon: CloudCog, path: '/platforms' },
       { id: 'cloud-billing', name: '云账单', icon: BarChart3, path: '/cloud-billing' },
-      { id: 'agent-monitor', name: 'Agent监控', icon: Activity, path: '/agent-monitor' },
     ],
   },
   {
@@ -84,14 +83,14 @@ const menuItems: MenuItem[] = [
   },
   {
     id: 'monitor',
-    name: '监控告警',
+    name: '监控中心',
     icon: Bell,
     children: [
+      { id: 'monitor-center', name: '资源监控', icon: Activity, path: '/monitor-center' },
       { id: 'metrics', name: '指标监控', icon: Cpu, path: '/metrics' },
-      { id: 'alert-center', name: '告警中心', icon: Bell, path: '/alert-center' },
-      { id: 'trace', name: '链路追踪', icon: GitBranch, path: '/trace' },
       { id: 'grafana', name: '监控大屏', icon: Monitor, path: '/grafana' },
-      { id: 'agent-alerts', name: 'Agent告警', icon: AlertTriangle, path: '/agent-alerts' },
+      { id: 'trace', name: '链路追踪', icon: GitBranch, path: '/trace' },
+      { id: 'alert-center', name: '告警服务', icon: Bell, path: '/alert-center' },
     ],
   },
   {

frontend/src/components/server/ServerManager.tsx

@@ -1,4 +1,4 @@
-import { useState, useEffect } from 'react';
+import { useState, useEffect, useRef } from 'react';
 import { cn } from '@/lib/utils';
 import { Card, CardContent } from '@/components/ui/card';
 import { Button } from '@/components/ui/button';
@@ -168,6 +168,82 @@ export function ServerManager() {
     loadData();
   }, []);
 
+  // WebSocket 实时接收 Agent 指标推送 // Logan.Li
+  const wsRef = useRef<WebSocket | null>(null);
+  const reconnectTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
+
+  useEffect(() => {
+    const token = useUserStore.getState().token;
+    if (!token) return;
+
+    const protocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
+    const wsUrl = `${protocol}//${window.location.host}/ws/metrics?token=${token}`;
+
+    const connect = () => {
+      if (wsRef.current?.readyState === WebSocket.OPEN) return;
+
+      const ws = new WebSocket(wsUrl);
+      wsRef.current = ws;
+
+      ws.onopen = () => {
+        console.log('[MetricsWS] 已连接，实时接收指标推送');
+      };
+
+      ws.onmessage = (event) => {
+        try {
+          const msg = JSON.parse(event.data);
+          if (msg.type === 'metrics_update') {
+            setServers((prev) =>
+              prev.map((s) => {
+                // 通过 hostname 匹配（Agent 上报时使用 hostname）
+                if (s.hostname === msg.hostname) {
+                  return {
+                    ...s,
+                    cpu_usage: msg.cpu_usage,
+                    memory_usage: msg.memory_usage,
+                    disk_usage: msg.disk_usage,
+                    status: msg.status,
+                    tcp_established: msg.tcp_established,
+                    tcp_time_wait: msg.tcp_time_wait,
+                    net_rx_bps: msg.net_rx_bps,
+                    net_tx_bps: msg.net_tx_bps,
+                    disk_read_bps: msg.disk_read_bps,
+                    disk_write_bps: msg.disk_write_bps,
+                  };
+                }
+                return s;
+              })
+            );
+          }
+        } catch (e) {
+          // 忽略非 JSON 消息
+        }
+      };
+
+      ws.onclose = () => {
+        console.log('[MetricsWS] 连接断开，3 秒后重连');
+        wsRef.current = null;
+        reconnectTimerRef.current = setTimeout(connect, 3000);
+      };
+
+      ws.onerror = (err) => {
+        console.error('[MetricsWS] 连接错误:', err);
+        ws.close();
+      };
+    };
+
+    connect();
+
+    return () => {
+      if (reconnectTimerRef.current) clearTimeout(reconnectTimerRef.current);
+      if (wsRef.current) {
+        wsRef.current.onclose = null; // 阻止自动重连
+        wsRef.current.close();
+        wsRef.current = null;
+      }
+    };
+  }, []);
+
   const filteredServers = servers.filter((server) => {
     const matchesSearch =
       (server.hostname || '').toLowerCase().includes(searchQuery.toLowerCase()) ||

frontend/src/components/server/ServerTableRow.tsx

@@ -12,7 +12,7 @@ import {
   DropdownMenuTrigger,
 } from '@/components/ui/dropdown-menu';
 import { TableCell, TableRow } from '@/components/ui/table';
-import { Cpu, Edit, Loader2, MoreHorizontal, Server as ServerIcon, Terminal, Trash2, CheckCircle, XCircle } from "lucide-react";
+import { Cpu, Edit, Loader2, MoreHorizontal, Server as ServerIcon, Terminal, Trash2, CheckCircle, XCircle, Network, HardDrive } from 'lucide-react';
 import { getStatusBadge, getTags, getUsageColor } from './serverHelpers';
 
 interface ServerTableRowProps {
@@ -42,6 +42,19 @@ export function ServerTableRow({
   const memoryUsage = Number(server.memory_usage || 0);
   const tags = getTags(server);
   const memGB = server.memory ? Math.round(server.memory / 1024) : 0;
+  const tcpEst = server.tcp_established || 0;
+  const tcpTw = server.tcp_time_wait || 0;
+  const rxBps = server.net_rx_bps || 0;
+  const txBps = server.net_tx_bps || 0;
+  const readBps = server.disk_read_bps || 0;
+  const writeBps = server.disk_write_bps || 0;
+
+  // Format bytes/s to human readable
+  const fmtBps = (bps: number) => {
+    if (bps >= 1_000_000) return (bps / 1_000_000).toFixed(1) + 'MB/s';
+    if (bps >= 1_000) return (bps / 1_000).toFixed(1) + 'KB/s';
+    return bps.toFixed(0) + 'B/s';
+  };
 
   return (
     <TableRow className="border-[var(--dg-border)] hover:bg-[var(--dg-bg-tertiary)]/50">
@@ -107,6 +120,15 @@ export function ServerTableRow({
             </div>
             <span className="text-xs text-[var(--dg-text-secondary)]">{memoryUsage.toFixed(1)}%</span>
           </div>
+          <div className="flex items-center gap-1 text-xs text-[var(--dg-text-muted)] pt-0.5">
+            <Network className="h-3 w-3" />
+            <span>{tcpEst}连接</span>
+            {tcpTw > 0 && <span className="text-[var(--dg-orange)]">({tcpTw}TW)</span>}
+          </div>
+          <div className="flex items-center gap-1 text-xs text-[var(--dg-text-muted)]">
+            <HardDrive className="h-3 w-3" />
+            <span>读{fmtBps(readBps)}/写{fmtBps(writeBps)}</span>
+          </div>
         </div>
       </TableCell>
       <TableCell>