fix(i18n): add Chinese translations for account settings page (#2712)

The account settings page had all user-facing strings (profile labels,
  password form placeholders, validation messages, button text) hardcoded
  in English. Replace them with i18n translation keys so the page renders
  correctly when the locale is set to Chinese.

 Fixed #2710

frontend/src/core/i18n/locales/zh-CN.ts

@@ -458,6 +458,23 @@ export const zhCN: Translations = {
       notSupported: "当前浏览器不支持通知功能。",
       disableNotification: "关闭通知",
     },
+    account: {
+      profileTitle: "个人信息",
+      email: "邮箱",
+      role: "角色",
+      changePasswordTitle: "修改密码",
+      changePasswordDescription: "更新你的账号密码。",
+      currentPassword: "当前密码",
+      newPassword: "新密码",
+      confirmNewPassword: "确认新密码",
+      passwordMismatch: "两次输入的新密码不一致",
+      passwordTooShort: "密码长度至少为 8 个字符",
+      passwordChangedSuccess: "密码修改成功",
+      networkError: "网络错误，请重试。",
+      updating: "更新中...",
+      updatePassword: "修改密码",
+      signOut: "退出登录",
+    },
     acknowledge: {
       emptyTitle: "致谢",
       emptyDescription: "相关的致谢信息会展示在这里。",