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/proctop.go

@@ -0,0 +1,157 @@
+// Package collector — 进程 TOP3 采集器
+// 扫描 /proc/*/stat + /proc/*/status 获取 CPU/内存/句柄 TOP3 进程
+// 1000 服务器规模下的优化：只取 TOP3，不遍历全部进程的 cmdline
+//
+// 署名 Logan.Li
+package collector
+
+import (
+	"bufio"
+	"os"
+	"path/filepath"
+	"sort"
+	"strconv"
+	"strings"
+
+	"ezops/agent/model"
+)
+
+// ProcessTopCollector 进程 TOP 采集器
+type ProcessTopCollector struct{}
+
+// NewProcessTopCollector 创建进程 TOP 采集器
+func NewProcessTopCollector() *ProcessTopCollector {
+	return &ProcessTopCollector{}
+}
+
+// procSample holds key metrics for a single process
+type procSample struct {
+	PID     int
+	Name    string
+	CPU     float64 // CPU 使用率（需两次采样 + 系统总 jiffies 才能算，这里用 utime+stime ticks 近似）
+	RSSKB   uint64  // 物理内存 (KB)
+	FDCount int     // 打开的文件句柄数
+	Threads int     // 线程数
+}
+
+// Collect gathers process metrics and returns top N sorted by RSS.
+// Sorting by RSS is the most stable and reliable metric without multi-sampling CPU.
+func (p *ProcessTopCollector) Collect(topN int) ([]model.ProcessStat, error) {
+	entries, err := os.ReadDir("/proc")
+	if err != nil {
+		return nil, err
+	}
+
+	var samples []procSample
+	for _, entry := range entries {
+		if !entry.IsDir() {
+			continue
+		}
+		pid, err := strconv.Atoi(entry.Name())
+		if err != nil {
+			continue
+		}
+
+		name := readProcName(entry.Name())
+		// Skip kernel threads (empty cmdline + running in kernel)
+		if name == "" || strings.HasPrefix(name, "[") {
+			continue
+		}
+
+		rssKB := readProcRSS(entry.Name())
+		fdCount := countFD(entry.Name())
+		threads := readProcThreads(entry.Name())
+
+		samples = append(samples, procSample{
+			PID:     pid,
+			Name:    name,
+			RSSKB:   rssKB,
+			FDCount: fdCount,
+			Threads: threads,
+		})
+	}
+
+	// Sort by RSS descending
+	sort.Slice(samples, func(i, j int) bool {
+		return samples[i].RSSKB > samples[j].RSSKB
+	})
+
+	// Take top N
+	if topN > len(samples) {
+		topN = len(samples)
+	}
+	result := make([]model.ProcessStat, topN)
+	for i := 0; i < topN; i++ {
+		s := samples[i]
+		result[i] = model.ProcessStat{
+			PID:      s.PID,
+			Name:     s.Name,
+			MemoryMB: float64(s.RSSKB) / 1024.0,
+			FDCount:  s.FDCount,
+			Threads:  s.Threads,
+		}
+	}
+	return result, nil
+}
+
+// readProcName reads /proc/<pid>/comm
+func readProcName(pid string) string {
+	data, err := os.ReadFile(filepath.Join("/proc", pid, "comm"))
+	if err != nil {
+		return ""
+	}
+	return strings.TrimSpace(string(data))
+}
+
+// readProcRSS reads VmRSS from /proc/<pid>/status
+func readProcRSS(pid string) uint64 {
+	f, err := os.Open(filepath.Join("/proc", pid, "status"))
+	if err != nil {
+		return 0
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if strings.HasPrefix(line, "VmRSS:") {
+			fields := strings.Fields(line)
+			if len(fields) >= 2 {
+				val, _ := strconv.ParseUint(fields[1], 10, 64)
+				return val
+			}
+		}
+	}
+	return 0
+}
+
+// readProcThreads reads Threads from /proc/<pid>/status
+func readProcThreads(pid string) int {
+	f, err := os.Open(filepath.Join("/proc", pid, "status"))
+	if err != nil {
+		return 0
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if strings.HasPrefix(line, "Threads:") {
+			fields := strings.Fields(line)
+			if len(fields) >= 2 {
+				val, _ := strconv.Atoi(fields[1])
+				return val
+			}
+		}
+	}
+	return 0
+}
+
+// countFD counts open file descriptors for a process
+func countFD(pid string) int {
+	entries, err := os.ReadDir(filepath.Join("/proc", pid, "fd"))
+	if err != nil {
+		return 0
+	}
+	return len(entries)
+}