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/system/SystemManager.tsx

@@ -3,14 +3,12 @@ import { useLocation } from 'react-router-dom';
 import { useConfirm } from '@/components/ui/confirm-dialog';
 import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs';
 import { Badge } from '@/components/ui/badge';
-import { CheckCircle, XCircle, Users, Shield, FileCode, Settings, TerminalSquare } from 'lucide-react';
+import { CheckCircle, XCircle, Users, Shield, Settings } from 'lucide-react';
 import { userApi } from '@/services/api';
 import type { Role } from '@/types';
 import { SystemUserTab } from './SystemUserTab';
 import { SystemRolesTab } from './SystemRolesTab';
-import { SystemLogsTab } from './SystemLogsTab';
 import { SystemSettingsTab } from './SystemSettingsTab';
-import { TerminalSessionsTab } from './TerminalSessionsTab';
 import { useLdapManagement } from './useLdapManagement';
 import type { UserFormData } from './UserFormDialog';
 
@@ -43,8 +41,6 @@ export function SystemManager() {
   const pathToTab: Record<string, string> = {
     '/users': 'users',
     '/roles': 'roles',
-    '/logs-audit': 'logs',
-    '/terminal-audit': 'terminal',
     '/settings': 'settings',
   };
   const [activeTab, setActiveTab] = useState(pathToTab[location.pathname] || 'users');
@@ -253,14 +249,6 @@ export function SystemManager() {
             <Shield className="h-4 w-4 mr-2" />
             角色权限
           </TabsTrigger>
-          <TabsTrigger value="logs" className="data-[state=active]:bg-slate-700">
-            <FileCode className="h-4 w-4 mr-2" />
-            操作审计
-          </TabsTrigger>
-          <TabsTrigger value="terminal" className="data-[state=active]:bg-slate-700">
-            <TerminalSquare className="h-4 w-4 mr-2" />
-            终端审计
-          </TabsTrigger>
           <TabsTrigger value="settings" className="data-[state=active]:bg-slate-700">
             <Settings className="h-4 w-4 mr-2" />
             系统设置
@@ -315,17 +303,6 @@ export function SystemManager() {
           />
         </TabsContent>
 
-        <TabsContent value="logs" className="mt-4 space-y-4">
-          <SystemLogsTab
-            searchQuery={searchQuery}
-            setSearchQuery={setSearchQuery}
-          />
-        </TabsContent>
-
-        <TabsContent value="terminal" className="mt-4 space-y-4">
-          <TerminalSessionsTab />
-        </TabsContent>
-
         <TabsContent value="settings" className="mt-4">
           <SystemSettingsTab {...ldap.settingsTabProps} />
         </TabsContent>