【引擎触发】每日签到：签到奖励与补签机制的引擎实现

function QF.SignIn(plr)
    local today = os.date("%Y%m%d")
    if plr.signDate == today then return false, "今日已签到" end
    local yesterday = os.date("%Y%m%d", os.time() - 86400)
    if plr.signDate == yesterday then
        plr.signCombo = (plr.signCombo or 0) + 1
    else
        plr.signCombo = 1
    end
    plr.signDate = today
    local reward = SIGN_REWARDS[math.min(plr.signCombo, 28)]
    plr:AddItemByName(reward.item, reward.n)
    plr:SendMsg("签到成功，连续签到 " .. plr.signCombo .. " 天")
    return true
end

function QF.MakeUpSign(plr, dateStr)
    if plr.signDate == dateStr then return false, "该日期已签到" end
    if not plr:HasItemByName("补签卡") then return false, "需要补签卡" end
    local signDay = tonumber(dateStr)
    local today = tonumber(os.date("%Y%m%d"))
    if today - signDay > 7 then return false, "仅可补签 7 天内" end
    plr:TakeItemByName("补签卡", 1)
    plr.signCombo = plr.signCombo + 1
    plr.signDate = dateStr
    plr:AddItemByName("签到补给", 1)
    return true
end