Detect the card network and tier (Visa, Mastercard, UnionPay and more) from the number prefix, entirely offline.
信用卡类型检测。根据卡号前缀(BIN)识别发卡组织与卡等级(如 Visa/Master/银联),用于表单校验与支付前端判断,纯前端检测不联网。