浏览器兑换独立成页面并按斗鱼模式优化导入

新增 /huya/browser-exchange 页面（精英宝典下方），支持导入账号与
执行兑换，客服仅见已分配账号；账号管理页移除该功能。导入弹窗对齐
斗鱼操作台：服务端分页筛选、可搜索标签、无 CK 不展示、导入本页/
一键导入全部/导入选中；新增 /accounts/ids 接口与 workbench
browser_exchange scope。

web/frontend/src/layouts/MainLayout.tsx

@@ -6,7 +6,7 @@ import {
   CloudServerOutlined, TeamOutlined, ApiOutlined, KeyOutlined,
   MenuFoldOutlined, MenuUnfoldOutlined, SwapOutlined,
   SunOutlined, MoonOutlined, DesktopOutlined, GiftOutlined, ShoppingCartOutlined, ApartmentOutlined, MobileOutlined,
-  BookOutlined, TrophyOutlined, ShopOutlined,
+  BookOutlined, TrophyOutlined, ShopOutlined, GlobalOutlined,
   SafetyCertificateOutlined, FileSearchOutlined,
 } from '@ant-design/icons';
 import { useNavigate, useLocation, Outlet } from 'react-router-dom';
@@ -96,6 +96,7 @@ export default function MainLayout({ onLogout }: { onLogout?: () => void }) {
   }
   if (can('huya:task')) {
     huyaItems.push({ key: '/huya/elite', label: '精英宝典', icon: <BookOutlined /> });
+    huyaItems.push({ key: '/huya/browser-exchange', label: '浏览器兑换', icon: <GlobalOutlined /> });
     huyaItems.push({ key: '/huya/tasks', label: '旧版任务台', icon: <ShoppingCartOutlined /> });
   }