fix(frontend): keep browser API on same-origin rewrites in dev

Document that NEXT_PUBLIC_WAVELET_BACKEND_URL must stay unset for local
next dev so axios hits /api/* and Next rewrites proxy to the backend.

frontend/app/(docs)/docs/how-to-use/page.tsx

@@ -1,17 +1,19 @@
+import { getTranslations } from 'next-intl/server';
 import { LegalPageLayout } from '@/components/common/docs/legal-page-layout';
-import { howToUseSections } from '@/components/common/docs/how-to-use';
+import { getHowToUseSections } from '@/components/common/docs/how-to-use';
 import { DOCS_LAST_UPDATED } from '@/components/common/docs/api';
 
-export default function HowToUsePage() {
+export default async function HowToUsePage() {
+  const t = await getTranslations('docs');
+
   return (
     <LegalPageLayout
-      title='平台使用指南'
+      title={t('howToUse.title')}
       lastUpdated={DOCS_LAST_UPDATED}
-      sections={howToUseSections}
+      sections={getHowToUseSections(t)}
       description={
         <p className='text-muted-foreground text-sm leading-relaxed'>
-          欢迎使用 Wavelet
-          脚手架系统。本文档将引导您快速了解平台的核心组件、角色权限设计及二次开发流程，帮助您快速上手开发。
+          {t('howToUse.description')}
         </p>
       }
     />