副本难度：三档难度的选择与奖励联动

local DIFF = {hp = 1.0, reward = 1.0}   -- 单档数值，两头不讨好

local DIFF = {
    easy = {hp = 0.6, reward = 0.5},
    normal = {hp = 1.0, reward = 1.0},
    hard = {hp = 1.8, reward = 2.0},
}
local function enter(actor, mode)
    local cfg = DIFF[mode] or DIFF.normal
    setplayvar(actor, "MOB_SCALE", cfg.hp)
    sendmsg(actor, 1, mode .. "难度：奖励 "
        .. cfg.reward .. " 倍")
end
enter(actor, "hard")