帮派商店：帮贡限购的周期刷新

-- 错误：限购计数不带周期，跨周永不清零
local n = getVar(p, "guildBought")
if n >= 5 then
    showTip(p, "本周限购已满")
    return
end

local LIMIT = 5
local function buyGuildGoods(p, goodsId)
    local week = os.date("%G-W%V")
    local key = "gBuy_" .. week .. "_" .. goodsId
    local n = getVar(p, key) or 0
    if n >= LIMIT then
        showTip(p, "本周限购 " .. LIMIT .. " 件")
        return
    end
    if (getVar(p, "guildPoint") or 0) < 200 then
        showTip(p, "帮贡不足")
        return
    end
    setVar(p, "guildPoint",
        getVar(p, "guildPoint") - 200)
    setVar(p, key, n + 1)
    giveGoods(p, goodsId)
end