fix(web): fix 401 unauthorized redirect not working properly (#997)

修复了token过期后页面一直遇到401错误、无法自动跳转登录页的问题
主要改动：
1. httpClient.ts
   - 去掉延迟跳转的setTimeout，改为立即跳转
   - 返回pending promise阻止SWR捕获401错误
   - 保存from401标记到sessionStorage，由登录页显示提示
2. LoginPage.tsx
   - 检测from401标记，显示"登录已过期"提示(永久显示)
   - 在登录成功时手动关闭过期提示toast
   - 支持管理员登录、普通登录、OTP验证三种场景
3. TraderConfigModal.tsx
   - 修复3处直接使用fetch()的问题，改为httpClient.get()
   - 确保所有API请求都经过统一的401拦截器
4. translations.ts
   - 添加sessionExpired的中英文翻译
修复效果：
- token过期时立即跳转登录页(无延迟)
- 登录页持续显示过期提示，直到用户登录成功或手动关闭
- 不会再看到401错误页面或重复的错误提示
Co-authored-by: tinkle-community <tinklefund@gmail.com>

web/src/components/TraderConfigModal.tsx

@@ -4,6 +4,7 @@ import { useLanguage } from '../contexts/LanguageContext'
 import { t } from '../i18n/translations'
 import { toast } from 'sonner'
 import { Pencil, Plus, X as IconX } from 'lucide-react'
+import { httpClient } from '../lib/httpClient'
 
 // 提取下划线后面的名称部分
 function getShortName(fullName: string): string {
@@ -114,7 +115,7 @@ export function TraderConfigModal({
   useEffect(() => {
     const fetchConfig = async () => {
       try {
-        const response = await fetch('/api/config')
+        const response = await httpClient.get('/api/config')
         const config = await response.json()
         if (config.default_coins) {
           setAvailableCoins(config.default_coins)
@@ -140,7 +141,7 @@ export function TraderConfigModal({
   useEffect(() => {
     const fetchPromptTemplates = async () => {
       try {
-        const response = await fetch('/api/prompt-templates')
+        const response = await httpClient.get('/api/prompt-templates')
         const data = await response.json()
         if (data.templates) {
           setPromptTemplates(data.templates)
@@ -198,19 +199,13 @@ export function TraderConfigModal({
         throw new Error('未登录，请先登录')
       }
 
-      const response = await fetch(
+      const response = await httpClient.get(
         `/api/account?trader_id=${traderData.trader_id}`,
         {
-          headers: {
-            Authorization: `Bearer ${token}`,
-          },
+          Authorization: `Bearer ${token}`,
         }
       )
 
-      if (!response.ok) {
-        throw new Error('获取账户余额失败')
-      }
-
       const data = await response.json()
 
       // total_equity = 当前账户净值（包含未实现盈亏）