feat(alert-center): 添加飞书Webhook通知渠道 + 告警引擎实时通知

- 后端: NotifyChannel 模型新增 feishu 类型, FeishuWebhookConfig
- 后端: TestNotifyChannel 真实发送飞书测试消息(文本格式)
- 后端: 告警引擎触发/恢复时自动发送飞书通知(sendFeishuAlert/sendFeishuRecovery)
- 后端: AlertEngine 新增 tcp_time_wait/tcp_close_wait/service_process 指标检测
- 后端: NetworkStatModel 新增 TCPCloseWait 字段
- 后端: QuickSetupRules 一键创建6条告警规则(CPU/内存/磁盘/TIME_WAIT/CLOSE_WAIT/进程)
- 后端: 注册 /alerts/quick-setup 路由
- 前端: AlertChannelDialog 新增飞书类型选项
- 前端: helpers 新增 getChannelIcon/getChannelTypeLabel 支持 feishu/dingtalk/wechat

agent/collector/swap.go

@@ -0,0 +1,76 @@
+// Package collector — Swap 采集器
+// 从 /proc/meminfo 读取 SwapTotal / SwapFree
+// 仅当系统有 swap 分区时返回有效数据
+//
+// 署名 Logan.Li
+package collector
+
+import (
+	"bufio"
+	"os"
+	"strings"
+
+	"ezops/agent/model"
+)
+
+// SwapCollector 交换分区采集器
+type SwapCollector struct{}
+
+// NewSwapCollector 创建 Swap 采集器
+func NewSwapCollector() *SwapCollector {
+	return &SwapCollector{}
+}
+
+// Collect 读取 swap 指标
+func (s *SwapCollector) Collect() (*model.SwapStat, error) {
+	f, err := os.Open("/proc/meminfo")
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	var swapTotal, swapFree uint64
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := scanner.Text()
+		fields := strings.Fields(line)
+		if len(fields) < 2 {
+			continue
+		}
+		// Line format: "SwapTotal:      0 kB"
+		key := strings.TrimSuffix(fields[0], ":")
+		switch key {
+		case "SwapTotal":
+			swapTotal, _ = parseUint64(fields[1])
+		case "SwapFree":
+			swapFree, _ = parseUint64(fields[1])
+		}
+	}
+
+	// No swap configured — return nil (caller should omit from report)
+	if swapTotal == 0 {
+		return nil, nil
+	}
+
+	used := swapTotal - swapFree
+	stat := &model.SwapStat{
+		TotalGB: float64(swapTotal) / (1024.0 * 1024.0),
+		UsedGB:  float64(used) / (1024.0 * 1024.0),
+	}
+	if swapTotal > 0 {
+		stat.UsagePercent = float64(used) / float64(swapTotal) * 100.0
+	}
+	return stat, nil
+}
+
+// parseUint64 parses a uint64 or returns 0
+func parseUint64(s string) (uint64, error) {
+	var v uint64
+	for _, c := range s {
+		if c < '0' || c > '9' {
+			break
+		}
+		v = v*10 + uint64(c-'0')
+	}
+	return v, nil
+}