The round trip, unbroken
Scan → order → fire → plate → pay → close. One order id travels the whole night; nothing is re-keyed, nothing is lost between the table and the pass.
Guest scans table QR
anon order, source=qr_code
Ticket hits the KDS
realtime, with a timer
Cashier settles
split cash / card / wallet
EOD balances itself
payments vs orders, logged