GET /user/profile

{
  id: string,
  nickname: string,
  avatarUrl: string,
  email: string,
  plan: string,                // free / basic / basic_year / pro / pro_year / max / max_year
  credit: number,              // 月度 credits（下月重置）
  addonCredits: number,        // Booster credits（持续）
  language: string,            // i18n 偏好
  watermark: boolean,          // 下载时自动加水印
  isOpenNotification: boolean,
  lastCreditIssuedAt: string | null
}