Get the calling application's wallet

Returns the current escrow wallet for the authenticated application including:

• balance – net position (credits − debits for all completed transactions)
• totalDebited – running sum of all outgoing accepted payments
• totalCredited – running sum of all incoming accepted payments

The wallet is auto-provisioned on the first transaction so calling this endpoint before any transaction is initiated will return a 404 until the wallet exists. Call POST /v1/wallet to provision it eagerly.