feat(client): i18n copy + reco lang refresh + home polish

client/src/services/recoApi.ts

@@ -35,13 +35,14 @@ function withTimeout(ms: number): AbortController {
 export async function fetchRecoFeed(req: RecoRequest): Promise<RecoEngineResult> {
   const controller = withTimeout(12_000);
   const url = `${API_BASE_URL}/v1/reco/feed`;
+  const acceptLanguage = i18n.language?.toLowerCase().startsWith('zh') ? 'tc' : 'en';
 
   const res = await fetch(url, {
     method: 'POST',
     headers: {
       'Content-Type': 'application/json',
       // 让后端做 locale 选择（目前后端只区分 en/tc）
-      'Accept-Language': i18n.language || 'en',
+      'Accept-Language': acceptLanguage,
     },
     body: JSON.stringify({
       k: req.k,