feat: 分站在线充值功能

- 新增 dist_topup.go 控制器，支持易支付/Stripe/Creem/加密货币充值
- 分站模型新增 enable_topup 字段
- 分站前端新增充值页面和导航入口
- 分站设置页新增充值开关
- 添加中英文 i18n 翻译

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/App.jsx

@@ -9,6 +9,7 @@ const Dashboard = lazy(() => import('./pages/Dashboard'));
 const Tokens = lazy(() => import('./pages/Tokens'));
 const Packages = lazy(() => import('./pages/Packages'));
 const Pricing = lazy(() => import('./pages/Pricing'));
+const Topup = lazy(() => import('./pages/Topup'));
 
 const Loading = () => (
   <div className="flex items-center justify-center min-h-screen">
@@ -34,6 +35,7 @@ function ThemedRoutes() {
           <Route element={<AuthGuard />}>
             <Route path="/dashboard" element={<Dashboard />} />
             <Route path="/tokens" element={<Tokens />} />
+            <Route path="/topup" element={<Topup />} />
           </Route>
         </Route>