Creates a deposit account for the given customer. A dedicated fiat bank account is provisioned
asynchronously, so this returns HTTP 202 with status provisioning and deposit_instructions set to
null. Once provisioning completes the account flips to active and the bank account the payer should
wire / ACH into is populated in deposit_instructions. Receive it by subscribing to the deposit_account
webhook (fired on activation, payload includes deposit_instructions) or by polling GET on the account.

The deposit account receives fiat for a single source country (source_country, currently US only) and
auto-converts it to crypto sent to destination. Travel Rule fields are supplied flat under destination
(aligned with the Transfer v2 on-ramp convention) and are reused when the matching on-ramp transfer is created.

Body parameters (with enum dropdowns) come from StoreCustomerDepositAccountRequest::rules() and
bodyParameters(), so OpenAPI consumers such as readme.io render the fixed-choice fields as dropdowns.