【后端接口】活跃度系统：每日任务点数与宝箱阶梯

---活跃度：任务完成累加活跃点
function Activity.addPoint(actor, taskType, point)
    local player = class(actor)
    if not player then return false end
    local dayKey = "Act_" .. os.date("%Y%m%d")
    local cur = tonumber(getplayvar(actor, 2, dayKey)) or 0
    if cur >= 100 then return false end
    setplayvar(actor, 2, dayKey, math.min(cur + point, 100), 0)
    -- 跨过宝箱阶梯的提示
    local before = math.floor(cur / 30)
    local after = math.floor((cur + point) / 30)
    if after > before then
        sendmsg(actor, 1, "活跃宝箱已解锁第 " .. after .. " 档！")
    end
    return true
end

---宝箱领取：按阶梯发奖，幂等标记
function Activity.claimChest(actor, tier)
    local player = class(actor)
    if not player then return false end
    local dayKey = "Act_" .. os.date("%Y%m%d")
    local cur = tonumber(getplayvar(actor, 2, dayKey)) or 0
    local need = tier * 30
    if cur < need then
        sendmsg(actor, 1, "活跃度不足 " .. need)
        return false
    end
    local claimKey = "Chest_" .. tier .. "_" .. os.date("%Y%m%d")
    if (getplayvar(actor, 2, claimKey) or "") ~= "" then
        sendmsg(actor, 1, "该档宝箱已领取")
        return false
    end
    setplayvar(actor, "HUMAN", claimKey, os.time(), 0)
    giveitem(actor, "活跃宝箱" .. tier, 1)
    sendmsg(actor, 1, "领取活跃宝箱 " .. tier .. " 档")
    return true
end