Card Limit and Rate Limit for Sub-Accounts

To prevent fraud, a restriction has been implemented allowing users to add only three cards to their accounts. If a user tries to add a new card when an existing one has expired, the system will automatically replace the old card with the new one, as long as the card fingerprint remains the same. Additionally, users are limited to five attempts per day to add cards using the Add Card API for sub-accounts. This includes both successful and failed attempts, ensuring a maximum of five attempts within a 24-hour period.