Accepted — the payroll passed the eligibility check and the teardown was
enqueued. The body is the payroll before deletion; poll the show
endpoint to confirm it is gone.

Not found — no bank_payroll with that id is visible to your company. The
lookup is company-scoped, so an id that exists but belongs to another
company also answers 404 (not 401).

Unprocessable entity — the payroll is not deletable. Both variants carry
a machine-readable error_code:

• payrolls/not_available: the payroll is not a clean draft (wrong
  status, or a transition already in flight).
• payrolls/terminal_transactions_present: the payroll holds transfers
  the bank already processed, so it can no longer be torn down.