Add a new platform external account

Register a new external bank account for the platform.

Sandbox Testing: In sandbox mode, use these account number patterns to test different transfer scenarios. These patterns should be used with the primary alias, address, or identifier of whatever account type you’re testing. For example, the US account number, a CLABE, an IBAN, a spark wallet address, etc. The failure patterns are:

• Account numbers ending in 002: Insufficient funds (transfer-in will fail)
• Account numbers ending in 003: Account closed/invalid (transfers will fail)
• Account numbers ending in 004: Transfer rejected (bank rejects the transfer)
• Account numbers ending in 009: Timeout/delayed failure (stays pending ~30s, then fails)
• Any other account number: Success (transfers complete normally)