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>

frontend/src/pages/monitor/site-monitor/helpers.ts

@@ -0,0 +1,144 @@
+// 站点拨测辅助函数 // Logan.Li
+
+export const PROBE_TYPE_OPTIONS = ['HTTP', 'SSL', 'TCP', 'DNS', 'PING'] as const;
+export type ProbeType = (typeof PROBE_TYPE_OPTIONS)[number];
+
+export interface SiteTask {
+  id: number;
+  name: string;
+  url: string;
+  type: string;
+  frequency_sec: number;
+  timeout_sec: number;
+  expected_status_code: number;
+  enabled: boolean;
+  last_status?: string;
+  last_response_time_ms?: number;
+  last_checked_at?: string;
+  success_rate?: number;
+  alert_status?: 'normal' | 'alerting';
+  created_at: string;
+  ssl_days_remaining?: number;
+  ssl_cert_expiry?: string;
+}
+
+export interface SiteResult {
+  id: number;
+  task_id: number;
+  status: string;
+  http_status_code?: number;
+  response_time?: number;
+  total_time: number;
+  remote_ip?: string;
+  error_message?: string;
+  checked_at: string;
+  ssl_days_remaining?: number;
+  ssl_cert_expiry?: string;
+  ssl_cert_issuer?: string;
+}
+
+export interface SiteStats {
+  total_tasks: number;
+  enabled_tasks: number;
+  up_count: number;
+  down_count: number;
+  availability: number;
+  probe_count: number;
+}
+
+export type SiteTimeRange = '1h' | '6h' | '24h' | '7d';
+
+export const SITE_TIME_RANGE_HOURS: Record<SiteTimeRange, number> = {
+  '1h': 1,
+  '6h': 6,
+  '24h': 24,
+  '7d': 168,
+};
+
+export const SITE_TIME_RANGE_LABELS: Record<SiteTimeRange, string> = {
+  '1h': '近 1 小时',
+  '6h': '近 6 小时',
+  '24h': '近 24 小时',
+  '7d': '近 7 天',
+};
+
+export const probeTypeMeta: Record<ProbeType, { label: string; placeholder: string; hint: string }> = {
+  HTTP: { label: '目标 URL', placeholder: 'https://example.com/health', hint: 'Web 请求（支持 http/https），检测状态码与响应时间' },
+  SSL: { label: 'SSL 地址', placeholder: 'example.com:443 或 https://example.com', hint: 'TLS 握手检测证书（支持 host:port / https:// 域名，不发起 HTTP 请求）' },
+  TCP: { label: '主机:端口', placeholder: '192.168.1.1:8080 或 example.com:443', hint: 'TCP 端口连通性' },
+  DNS: { label: '域名', placeholder: 'example.com', hint: 'DNS 解析延迟与结果' },
+  PING: { label: '主机地址', placeholder: '192.168.1.1 或 example.com', hint: 'ICMP 连通性与延迟' },
+};
+
+/** 拨测频率展示 // Logan.Li */
+export function fmtFrequency(sec?: number): string {
+  if (!sec) return '--';
+  if (sec < 60) return `${sec}秒`;
+  if (sec < 3600) return `${Math.round(sec / 60)}分钟`;
+  return `${(sec / 3600).toFixed(1)}小时`;
+}
+
+/** 可用率 / 响应时间组合展示 // Logan.Li */
+export function fmtAvailResponse(task: Pick<SiteTask, 'success_rate' | 'last_response_time_ms'>): string {
+  const avail = task.success_rate != null && task.success_rate >= 0
+    ? `${task.success_rate.toFixed(1)}%`
+    : '--';
+  return `${avail} / ${fmtMs(task.last_response_time_ms)}`;
+}
+
+export function fmtMs(ms?: number): string {
+  if (ms == null) return '--';
+  if (ms < 1) return '0ms';
+  if (ms < 1000) return `${Math.round(ms)}ms`;
+  return `${(ms / 1000).toFixed(2)}s`;
+}
+
+/** 列表时间：MM-DD HH:mm // Logan.Li */
+export function fmtTime(iso?: string): string {
+  if (!iso) return '--';
+  const d = new Date(iso);
+  const pad = (n: number) => String(n).padStart(2, '0');
+  return `${pad(d.getMonth() + 1)}-${pad(d.getDate())} ${pad(d.getHours())}:${pad(d.getMinutes())}`;
+}
+
+/** SSL 证书预警阈值（天）// Logan.Li */
+export const SSL_EXPIRY_WARN_DAYS = 30;
+
+/** 是否为 SSL 证书拨测任务 // Logan.Li */
+export function isSslProbeTask(task: Pick<SiteTask, 'type'>): boolean {
+  const t = task.type?.toUpperCase();
+  return t === 'SSL' || t === 'HTTPS';
+}
+
+/** 证书是否进入预警期（默认 < 30 天）// Logan.Li */
+export function isSslExpiringSoon(days?: number, threshold = SSL_EXPIRY_WARN_DAYS): boolean {
+  return days != null && days < threshold;
+}
+
+/** SSL 证书剩余天数展示 // Logan.Li */
+export function fmtSslDays(days?: number): { text: string; tone: string } {
+  if (days == null) return { text: '--', tone: 'text-[var(--dg-text-muted)]' };
+  if (days < 0) return { text: '已过期', tone: 'dg-text-red' };
+  if (days <= 7) return { text: `${days}天`, tone: 'dg-text-red' };
+  if (days <= 30) return { text: `${days}天`, tone: 'dg-text-yellow' };
+  return { text: `${days}天`, tone: 'dg-text-green' };
+}
+
+/** 归一化拨测协议类型 // Logan.Li */
+export function normalizeProbeType(raw?: string): ProbeType {
+  const upper = (raw || 'HTTP').toUpperCase();
+  if (upper === 'HTTPS') return 'HTTP';
+  if (PROBE_TYPE_OPTIONS.includes(upper as ProbeType)) return upper as ProbeType;
+  return 'HTTP';
+}
+
+export function isHttpProbeTask(task: Pick<SiteTask, 'type'>): boolean {
+  return normalizeProbeType(task.type) === 'HTTP';
+}
+
+export function fmtChartTime(iso?: string): string {
+  if (!iso) return '';
+  const d = new Date(iso);
+  const pad = (n: number) => String(n).padStart(2, '0');
+  return `${pad(d.getHours())}:${pad(d.getMinutes())}`;
+}