【框架设计】摆摊系统：线下挂单与离线交易实现

function Stall.list(plr, slot, price)
    local item = plr.bag[slot]
    if not item or item.bind then return false, "绑定物品不可出售" end
    if price < 100 or price > 99999999 then return false, "价格越界" end
    plr.bag[slot] = nil
    local stand = {
        owner = plr.id, item = item, price = price,
        city = plr.mapId, at = os.time(),
    }
    stallBoard[plr.id .. ":" .. slot] = stand
    return true
end

function Stall.buy(buyer, standKey)
    local stand = stallBoard[standKey]
    if not stand then return false, "商品已售出" end
    if not QF_CostGold(buyer, stand.price) then return false, "金币不足" end
    QF_GiveItem(buyer, stand.item)
    QF_MailGold(stand.owner, math.floor(stand.price * 0.95), "摆摊售出")
    stallBoard[standKey] = nil
    QF_LogTrade("stall", buyer.id, stand.owner, stand.item.id, stand.price)
    return true
end