crew ? 0 : total (and crew ? 1 : 0 in the insert) only work correctly if
crew is actually a boolean. Any other truthy value — the string "false"
is the obvious one, but any stray object/number works too — silently
books a paid sale as a free crew drink. Once total_cents is 0 there's
nothing left in the row to tell a genuine crew drink apart from a
mis-typed paid one; unrecoverable after the fact.
Adds the same typeof check the other fields on this endpoint already get
(isValidCents, qty bounds, etc.) — reject with 400 instead of silently
mis-booking.
22aa069b35