Wasn't the Offline Shop extension created originally by nostr:npub180cvv07tjdrrgpa0j7j7tmnyl2yr6yr7l8j4s3evf6u64th6gkwsyjh6w6 ?
https://github.com/lnbits/offlineshop
Yeah, he literally made a solution years ago and forgot.
Although for busy shop, lnpos would be better suited (based partly on offlineshop)
Although for busy shop, lnpos would be better suited (based partly on offlineshop)