Record a comped order — work promised without a payment

The comp path, and the same argument as granting a boost by hand: comping is real, and the alternative is writing a fake Payment row to make the queue look right, which would corrupt the one table that reconciles against Stripe. So this creates no Payment row and the order's paymentId stays null.

Every field but kind is optional. An operator arranging a guest post over email may have only an address at this point, and refusing the row until the brief is complete is how the order ends up not recorded at all.

Fires order.received, with the same keys a paid order sends and nulls where the payment would have been.