师门任务链：连续任务进度永久保存

-- 错误：进度键带日期，跨零点自动清零
local key = "chain_" .. os.date("%Y%m%d")
setplayvar(p, key, step)

local CHAIN = {5101, 5102, 5103, 5104, 5105}
local function onChainTask(p, taskId)
    local step = getplayvar(p, "chainStep") or 1
    if step > #CHAIN then return end
    if taskId ~= CHAIN[step] then return end
    setplayvar(p, "chainStep", step + 1)
    giveitem(p, 8701, 1)
    sendmsg(p, 1, "第 " .. step .. " 环完成")
    if step == #CHAIN then
        giveitem(p, 8799, 1)
        sendmsg(p, 1, "任务链达成，终章奖励已发")
    end
end