feat(l10n): 账户入口 redeemEntry 改「Redeem」(去掉「& buy」,购买已独立成购买套餐行)

6 语言:Redeem/兑换/コード引き換え/코드 등록/Активация/Canjear;account golden 重录。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013nMthbVEmQquxBRKb9Fj8u

client/lib/l10n/strings_zh.dart

@@ -197,7 +197,7 @@ class StringsZh extends AppText {
   @override
   String get sessionRevokedOk => '重新登录';
   @override
-  String get redeemEntry => '兑换 & 购买';
+  String get redeemEntry => '兑换';
   @override
   String get contactEntry => '联系我们';
   @override