fix: AlertCenter崩溃修复——字段名映射+notify_channels安全解析

- AlertRule接口与后端对齐(id:number/notify_channels:string)
- 告警事件数据映射(rule_name→title, message→description, target→source)
- notify_channels安全解析(JSON.parse+try-catch替代直接.map)
- labels/annotations字符串转对象安全处理
- Header tab栏移除(侧边栏导航足够)
- SQL审计API改为真实后端调用

frontend/src/components/layout/Header.tsx

@@ -1,6 +1,6 @@
 import { useState } from 'react';
 import { cn } from '@/lib/utils';
-import { useThemeStore, useTabStore, useNotificationStore, useUserStore } from '@/store';
+import { useThemeStore, useNotificationStore, useUserStore } from '@/store';
 import { Button } from '@/components/ui/button';
 import { Input } from '@/components/ui/input';
 import { Badge } from '@/components/ui/badge';
@@ -17,7 +17,6 @@ import {
   Search,
   Bell,
   Menu,
-  X,
   Settings,
   User,
   LogOut,
@@ -33,7 +32,6 @@ import { useTheme, THEME_OPTIONS } from '@/hooks/useTheme';
 
 export function Header() {
   const { sidebarCollapsed, toggleSidebar } = useThemeStore();
-  const { tabs, activeTab, removeTab, setActiveTab } = useTabStore();
   const { notifications, unreadCount, markAsRead, markAllAsRead } = useNotificationStore();
   const { user, logout } = useUserStore();
   const { theme, setTheme } = useTheme();
@@ -226,36 +224,7 @@ export function Header() {
         </div>
       </div>
 
-      {/* Tabs */}
-      {tabs.length > 0 && (
-        <div className="flex items-center h-9 px-2 bg-slate-950 border-b border-slate-800 overflow-x-auto">
-          {tabs.map((tab) => (
-            <div
-              key={tab.id}
-              className={cn(
-                'group flex items-center gap-2 px-3 py-1.5 text-sm border-r border-slate-800 cursor-pointer transition-colors whitespace-nowrap',
-                activeTab === tab.id
-                  ? 'bg-slate-900 text-slate-100'
-                  : 'text-slate-500 hover:text-slate-300 hover:bg-slate-900/50'
-              )}
-              onClick={() => setActiveTab(tab.id)}
-            >
-              <span>{tab.title}</span>
-              {tab.closable && (
-                <button
-                  className="opacity-0 group-hover:opacity-100 p-0.5 rounded hover:bg-slate-700 transition-all"
-                  onClick={(e) => {
-                    e.stopPropagation();
-                    removeTab(tab.id);
-                  }}
-                >
-                  <X className="h-3 w-3" />
-                </button>
-              )}
-            </div>
-          ))}
-        </div>
-      )}
+      {/* Tabs 已移除 — 侧边栏导航已足够，tab 栏多余且遮挡内容 */}
     </header>
   );
 }