feat: 监控告警体系统一重构 + 自动化任务调度引擎 + 监控大屏拆分

告警中心
- 新增统一告警(alert_unified)、监控告警规则(monitor_alert_rule)、指标目录(alert_metric_catalog)
- 通知策略与消息分发(alert_notify_policy/dispatch/message)、静默规则
- 告警引擎按阈值/SNMP 拆分(alert_engine_monitor/snmp)

监控采集
- SNMP 常量/模板与历史指标(snmp templates/constants、snmp_metrics_history、snmp_collect)
- 中间件监控 Redis 采集与种子(middleware_monitor_redis/seed)
- 站点探测 pkg(siteprobe) + 站点视图(site_view)

自动化任务
- cron 调度器(cronscheduler)、脚本运行器(scriptrunner)、系统任务(systask)及运行记录(cron_job_run、system_task)

审计与凭证
- 审计设置(audit_setting) + 历史清理(auditcleaner)

前端
- 监控页面(host/middleware/site/snmp)拆分为子模块并大屏化
- 告警中心多 Tab(规则/指标目录/通知策略/静默)、任务管理组件重构、Agent CLI Markdown 渲染
- 移除旧脚本卡片/详情/日志组件，统一为 ScriptTable/ScriptCodeEditor/TerminalOutput

Co-Authored-By: Claude <noreply@anthropic.com>

backend/controller/alert_notify_policy.go

@@ -0,0 +1,129 @@
+package controller
+
+import (
+	"encoding/json"
+	"net/http"
+	"strings"
+
+	"ezops/model"
+
+	"github.com/gin-gonic/gin"
+)
+
+// categoryLabels 告警集合中文名 // Logan.Li
+var categoryLabels = map[model.AlertNotifyCategory]string{
+	model.AlertNotifyHost:       "主机监控",
+	model.AlertNotifyMiddleware: "中间件监控",
+	model.AlertNotifySite:       "站点拨测",
+	model.AlertNotifySNMP:       "SNMP 监控",
+}
+
+// ensureNotifyPolicies 确保四类默认策略存在 // Logan.Li
+func (h *AlertHandler) ensureNotifyPolicies() {
+	for _, cat := range model.AllAlertNotifyCategories {
+		var p model.AlertNotifyPolicy
+		h.db.Where("category = ?", cat).First(&p)
+		if p.ID == 0 {
+			h.db.Create(&model.AlertNotifyPolicy{
+				Category: cat,
+				Label:    categoryLabels[cat],
+				Enabled:  false,
+			})
+		}
+	}
+}
+
+// ListNotifyPolicies GET /alerts/notify-policies
+func (h *AlertHandler) ListNotifyPolicies(c *gin.Context) {
+	h.ensureNotifyPolicies()
+	var policies []model.AlertNotifyPolicy
+	h.db.Order("id ASC").Find(&policies)
+	c.JSON(http.StatusOK, model.Response{Code: 200, Data: gin.H{"list": policies, "total": len(policies)}})
+}
+
+// UpsertNotifyPolicy PUT /alerts/notify-policies/:category
+func (h *AlertHandler) UpsertNotifyPolicy(c *gin.Context) {
+	cat := model.AlertNotifyCategory(strings.TrimSpace(c.Param("category")))
+	if !isValidNotifyCategory(cat) {
+		c.JSON(http.StatusBadRequest, model.Response{Code: 400, Message: "无效的告警集合类型"})
+		return
+	}
+
+	var req struct {
+		Enabled         *bool  `json:"enabled"`
+		ContactGroupIDs []uint `json:"contact_group_ids"`
+		ContactIDs      []uint `json:"contact_ids"`
+		NotifyMode      string `json:"notify_mode"`
+		Description     string `json:"description"`
+	}
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, model.Response{Code: 400, Message: "请求参数错误: " + err.Error()})
+		return
+	}
+
+	h.ensureNotifyPolicies()
+	var policy model.AlertNotifyPolicy
+	h.db.Where("category = ?", cat).First(&policy)
+
+	updates := map[string]interface{}{}
+	if req.Enabled != nil {
+		updates["enabled"] = *req.Enabled
+	}
+	if req.ContactGroupIDs != nil {
+		b, _ := json.Marshal(req.ContactGroupIDs)
+		updates["contact_group_ids"] = string(b)
+	}
+	if req.ContactIDs != nil {
+		b, _ := json.Marshal(req.ContactIDs)
+		updates["contact_ids"] = string(b)
+	}
+	if req.NotifyMode != "" {
+		updates["notify_mode"] = req.NotifyMode
+	}
+	if req.Description != "" || c.Request.ContentLength > 0 {
+		updates["description"] = req.Description
+	}
+
+	if len(updates) > 0 {
+		h.db.Model(&policy).Updates(updates)
+	}
+	h.db.Where("category = ?", cat).First(&policy)
+	c.JSON(http.StatusOK, model.Response{Code: 200, Data: policy})
+}
+
+// TestNotifyPolicy POST /alerts/notify-policies/:category/test
+func (h *AlertHandler) TestNotifyPolicy(c *gin.Context) {
+	cat := model.AlertNotifyCategory(strings.TrimSpace(c.Param("category")))
+	if !isValidNotifyCategory(cat) {
+		c.JSON(http.StatusBadRequest, model.Response{Code: 400, Message: "无效的告警集合类型"})
+		return
+	}
+	h.ensureNotifyPolicies()
+	var policy model.AlertNotifyPolicy
+	h.db.Where("category = ?", cat).First(&policy)
+
+	label := categoryLabels[cat]
+	title := buildNotifyTitle(h.db, "通知策略测试", label, "test", "info")
+	content := buildAlertContent("通知策略测试", label, "test", "info",
+		"这是一条测试通知，用于验证该告警集合的通知对象配置是否正确。", 0, 0)
+
+	sent, skipped := dispatchToPolicyContacts(h.db, &policy, title, content, "info", true)
+	if sent == 0 {
+		msg := "未发送任何通知"
+		if skipped > 0 {
+			msg += "（策略未启用或未配置联系人）"
+		}
+		c.JSON(http.StatusBadRequest, model.Response{Code: 400, Message: msg})
+		return
+	}
+	c.JSON(http.StatusOK, model.Response{Code: 200, Data: gin.H{"sent": sent, "skipped": skipped}, Message: "测试通知已发送"})
+}
+
+func isValidNotifyCategory(cat model.AlertNotifyCategory) bool {
+	for _, c := range model.AllAlertNotifyCategories {
+		if c == cat {
+			return true
+		}
+	}
+	return false
+}