Display a tailored confirmation message when the customer pays by
check or wire transfer, including a warning about the 30-day
cancellation policy. The payment type is passed as a query parameter
so the message survives page reloads.
- Add ``getOrderConfirmedByCheckContent()`` and
``getOrderConfirmedByWireContent()`` to ``Contents`` repository
- Flash ``payment_type`` through redirect query parameter
- Add migration inserting content rows (id 10, 11)
- Update confirmed view with green checkmark and warning icon
