fix(client): correct the Chinese hero slogan to 探索未至之境

The shipped copy read 探索未知之境; the product slogan is 探索未至之境.
English copy is untouched.

packages/client/ui-conversation/src/client/locales.ts

@@ -60,7 +60,7 @@ export const zh = {
   'access.confirm.acknowledge': '我已了解风险，并愿意继续',
   'access.confirm.cancel': '取消',
   'access.confirm.enable': '启用 Full access',
-  'hero.headline': '探索未知之境',
+  'hero.headline': '探索未至之境',
   'hero.preview': '预览版',
   'hero.chooseWorkspace': '选择工作区',
   'session.hierarchy': '会话层级',