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

backend/internal/api/handlers/agent.go

@@ -19,12 +19,13 @@ import (
 
 // AgentHandler 处理 Agent 上报数据 // Logan.Li
 type AgentHandler struct {
-	db    *gorm.DB
-	cache ezredis.Cache // 可选 Redis 缓存（用于热数据存储）
+	db         *gorm.DB
+	cache      ezredis.Cache // 可选 Redis 缓存（用于热数据存储）
+	hubMetrics *MetricsHub   // WebSocket 广播 metrics 更新
 }
 
-func NewAgentHandler(db *gorm.DB, cache ezredis.Cache) *AgentHandler {
-	return &AgentHandler{db: db, cache: cache}
+func NewAgentHandler(db *gorm.DB, cache ezredis.Cache, hub *MetricsHub) *AgentHandler {
+	return &AgentHandler{db: db, cache: cache, hubMetrics: hub}
 }
 
 // ReceiveReport 接收 Agent 上报的指标数据
@@ -47,6 +48,8 @@ func (h *AgentHandler) ReceiveReport(c *gin.Context) {
 	// 序列化磁盘和端口信息
 	diskJSON, _ := json.Marshal(req.Disks)
 	portJSON, _ := json.Marshal(req.Ports)
+	netJSON, _ := json.Marshal(req.Network)
+	dioJSON, _ := json.Marshal(req.DiskIO)
 
 	// 存储到数据库
 	report := models.AgentReport{
@@ -61,6 +64,8 @@ func (h *AgentHandler) ReceiveReport(c *gin.Context) {
 		MemUsage:   req.Memory.UsagePercent,
 		DiskInfo:   string(diskJSON),
 		PortInfo:   string(portJSON),
+		NetInfo:    string(netJSON),
+		DiskIOInfo: string(dioJSON),
 		ReportTime: reportTime,
 	}
 
@@ -69,6 +74,35 @@ func (h *AgentHandler) ReceiveReport(c *gin.Context) {
 		return
 	}
 
+	// 同步更新 servers 表的实时指标（通过 hostname 匹配）
+	diskAvg := avgDiskUsage(req.Disks)
+	result := h.db.Model(&models.Server{}).
+		Where("hostname = ? OR ip = ?", req.Hostname, req.Hostname).
+		Updates(map[string]interface{}{
+			"cpu_usage":    req.CPU.UsagePercent,
+			"memory_usage": req.Memory.UsagePercent,
+			"disk_usage":   diskAvg,
+			"status":       "running",
+		})
+
+	// WebSocket 广播：向所有前端客户端推送该主机的最新指标 // Logan.Li
+	if h.hubMetrics != nil && result.RowsAffected > 0 {
+		h.hubMetrics.Broadcast(MetricsUpdate{
+			Type:           "metrics_update",
+			Hostname:       req.Hostname,
+			CPU:            req.CPU.UsagePercent,
+			Memory:         req.Memory.UsagePercent,
+			Disk:           diskAvg,
+			Status:         "running",
+			TCPEstablished: req.Network.TCPEstablished,
+			TCPTimeWait:    req.Network.TCPTimeWait,
+			NetRxBPS:       req.Network.NetRxBPS,
+			NetTxBPS:       req.Network.NetTxBPS,
+			DiskReadBPS:    req.DiskIO.ReadBPS,
+			DiskWriteBPS:   req.DiskIO.WriteBPS,
+		})
+	}
+
 	// 写入 Redis 有序集合（热数据，保留7天）
 	if h.cache != nil {
 		timestamp := float64(reportTime.Unix())
@@ -169,6 +203,7 @@ func (h *AgentHandler) AggregateMetrics(c *gin.Context) {
 		duration time.Duration
 	}{
 		{"1m", 1 * time.Minute},
+		{"5m", 5 * time.Minute},
 		{"3m", 3 * time.Minute},
 		{"1h", 1 * time.Hour},
 		{"6h", 6 * time.Hour},
@@ -283,11 +318,20 @@ func (h *AgentHandler) GetKline(c *gin.Context) {
 	}
 
 	var klines []models.MetricsKline
-	h.db.Where("hostname = ? AND metric = ? AND interval = ? AND bucket_time >= ? AND bucket_time <= ?",
+	result := h.db.Where("hostname = ? AND metric = ? AND `interval` = ? AND bucket_time >= ? AND bucket_time <= ?",
 		req.Hostname, req.Metric, req.Interval, from, to).
 		Order("bucket_time ASC").
 		Find(&klines)
 
+	if result.Error != nil {
+		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "查询失败: " + result.Error.Error()})
+		return
+	}
+
+	if klines == nil {
+		klines = []models.MetricsKline{}
+	}
+
 	c.JSON(http.StatusOK, models.Response{
 		Code:    200,
 		Message: "success",
@@ -305,3 +349,15 @@ func parseMemberValue(member string) float64 {
 	v, _ := strconv.ParseFloat(member[:idx], 64)
 	return v
 }
+
+// avgDiskUsage 计算磁盘平均使用率
+func avgDiskUsage(disks []models.DiskMetric) float64 {
+	if len(disks) == 0 {
+		return 0
+	}
+	var sum float64
+	for _, d := range disks {
+		sum += d.UsagePercent
+	}
+	return math.Round(sum/float64(len(disks))*100) / 100
+}