feat(audit): F1+F2 告警静默规则标记完成 + 审计日志CSV导出实现

F1 告警静默规则 [done]:
- 后端 alert_silence.go: CRUD + Toggle (onetime/daily/weekly 三模式)
- 告警引擎 isSilenced 集成 (alert_engine.go)
- 前端 SilenceRuleTab + SilenceDialog
- 路由 /alerts/silences 已注册

F2 审计日志导出 [done]:
- 重写 ExportAuditLogs: 真正的 CSV 导出 (encoding/csv + UTF-8 BOM)
- 支持 module/action/username/startTime/endTime 筛选
- 导出限制 10000 条防溢出，自动记录审计日志
- JSON 格式向后兼容 (format=json)
- 前端 exportLogs 传递查询参数

同时包含累积的前期工作:
- 目录重构 internal/ -> controller/model/router (v0.55-v0.57)
- 后端分层架构 dto/repository/service/utils
- 审计模块全功能 (终端审计/操作审计/登录日志)
- asciicast v2 录制格式
- SFTP 文件浏览器
- StatStrip 紧凑统计条
- 在线会话自动刷新
- LiveMonitor WebSocket 诊断修复

验证: go build ✅ | npm run build ✅ | Docker 部署 ✅ | 10 回归端点 ✅ | CSV 导出 ✅ | 静默 CRUD ✅

frontend/src/components/dashboard/Dashboard.tsx

@@ -2,10 +2,10 @@ import { useCallback, useEffect, useState } from 'react';
 import { useNavigate } from 'react-router-dom';
 import { Button } from '@/components/ui/button';
 import { cn } from '@/lib/utils';
-import { Clock, Server, Cloud, Bell, DollarSign, ArrowRight} from 'lucide-react';
+import { Clock, Server, ArrowRight } from 'lucide-react';
 import { dashboardStatsApi, serverApi, kubernetesApi } from '@/services/api';
-import { StatCard } from './DashboardStats';
-import { CostOverviewCard, TopResourceUsageCard, ResourceUsageCard, computeMonthChange } from './DashboardCharts';
+import { StatStrip } from '@/components/ui/stat-strip';
+import { CostOverviewCard, TopResourceUsageCard, ResourceUsageCard } from './DashboardCharts';
 import {
   AlertMessagesCard,
   CertificateExpiryCard,
@@ -98,7 +98,6 @@ export function Dashboard() {
   const k8sStats = stats?.kubernetes_stats;
   const alertStats = stats?.alert_stats;
   const costStats = stats?.cost_stats;
-  const costChange = computeMonthChange(costStats?.month_trend);
 
   return (
     <div className="dg-page">
@@ -129,56 +128,19 @@ export function Dashboard() {
         </div>
       </div>
 
-      {/* Stats Grid with staggered animation */}
-      <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-4 gap-4">
-        <div className="animate-fade-in-delay-1">
-          <StatCard
-            title="服务器总数"
-            value={serverStats?.total ?? 0}
-            description={`${serverStats?.running ?? 0} 台运行中`}
-            icon={Server}
-            trend={Number(serverStats?.error ?? 0) > 0 ? 'down' : 'neutral'}
-            trendValue={Number(serverStats?.error ?? 0) > 0 ? `${serverStats?.error} 台异常` : '运行正常'}
-            color="blue"
-            onClick={() => navigate('/servers')}
-          />
-        </div>
-        <div className="animate-fade-in-delay-2">
-          <StatCard
-            title="Kubernetes 集群"
-            value={k8sStats?.total ?? 0}
-            description={`${k8sStats?.healthy ?? 0} 个健康`}
-            icon={Cloud}
-            trend="neutral"
-            trendValue="稳定"
-            color="purple"
-            onClick={() => navigate('/kubernetes')}
-          />
-        </div>
-        <div className="animate-fade-in-delay-3">
-          <StatCard
-            title="待处理告警"
-            value={alertStats?.firing ?? 0}
-            description={`${alertStats?.critical ?? 0} 个严重`}
-            icon={Bell}
-            trend={Number(alertStats?.today_count ?? 0) > 0 ? 'up' : 'down'}
-            trendValue={`本周 ${alertStats?.week_count ?? 0} 条`}
-            color="rose"
-            onClick={() => navigate('/alert-center')}
-          />
-        </div>
-        <div className="animate-fade-in-delay-4">
-          <StatCard
-            title="本月云成本"
-            value={`¥${Number(costStats?.month_cost ?? 0).toLocaleString()}`}
-            description={costChange.label}
-            icon={DollarSign}
-            trend={costChange.direction}
-            trendValue={`${costChange.pct > 0 ? '+' : ''}${costChange.pct.toFixed(1)}%`}
-            color="orange"
-            onClick={() => navigate('/cloud-billing')}
-          />
-        </div>
+      {/* Stats — compact strip */}
+      <div className="animate-fade-in-delay-1">
+        <StatStrip
+          items={[
+            { label: '服务器', value: serverStats?.total ?? 0, color: 'blue' },
+            { label: '运行中', value: serverStats?.running ?? 0, color: 'emerald' },
+            { label: 'K8s 集群', value: k8sStats?.total ?? 0, color: 'purple' },
+            { label: '健康集群', value: k8sStats?.healthy ?? 0, color: 'cyan' },
+            { label: '告警', value: alertStats?.firing ?? 0, color: alertStats?.firing > 0 ? 'red' : 'muted' },
+            { label: '严重', value: alertStats?.critical ?? 0, color: 'red' },
+            { label: '本月成本', value: `¥${Number(costStats?.month_cost ?? 0).toLocaleString()}`, color: 'amber' },
+          ]}
+        />
       </div>
 
       {/* Resource Usage Chart */}