Build a Stripe Treasury InboundTransfer from a Stripe Financial Connections linked bank account and handle the settling state

Steps

1. Ensure you have an active Stripe Treasury financial account and that the customer's external bank account is linked via Stripe Financial Connections with the payment permission
2. Create an InboundTransfer by posting to the treasury/inbound_transfers endpoint specifying the origin_payment_method (the linked bank account), amount, and currency
3. The InboundTransfer starts in processing status; subscribe to the treasury.inbound_transfer.succeeded and treasury.inbound_transfer.failed webhook events
4. On the succeeded event, the funds are available in the financial account balance; update your internal ledger
5. On a failed event, inspect the failure_details.code to distinguish between insufficient_funds, account_closed, and other return reasons
6. For the amount in settling status, note that funds are reserved but not yet spendable; plan treasury outflows only after the succeeded event