Barter Stalls

Build an owned barter-stall from 8 planks and 6 wood. Its merchant may hold up to 20 exact-stack offers within a 150 kg and 250 litre display chest. Buyers trade while the seller is away; exact quality and wear transfer atomically, payment remains physically held for seller collection, and escrow weathers naturally. Empty every offer and collect sold proceeds before unbuilding.
Exact JSON
"Build an owned barter-stall from 8 planks and 6 wood. Its merchant may hold up to 20 exact-stack offers within a 150 kg and 250 litre display chest. Buyers trade while the seller is away; exact quality and wear transfer atomically, payment remains physically held for seller collection, and escrow weathers naturally. Empty every offer and collect sold proceeds before unbuilding."