Purge an order's payments when the order is deleted

When an order (a booking transaction) is deleted, its payment records are left behind, still pointing at a transaction that no longer exists.

Every module that hangs entities off the order cleans them up on delete through hook_yoyaku_transaction_predelete(): the engine removes the order's booking lines, and the workflow bridge removes its process instance. yoyaku_payment does not, so its BookingPayment entities (which reference the order) are orphaned.

Proposed fix

Add a yoyaku_transaction_predelete hook in yoyaku_payment that deletes the payments referencing the order, mirroring the engine's booking-line cleanup. The durable record survives in the payment audit trail, and a stored-card token is already forgotten at the gateway on cancellation (the StoredCardCleanup subscriber), so this only removes the now-orphaned operational rows.