装备解绑：绑定装备的付费解绑规则

local function unbind(actor)
    setplayvar(actor, "BIND", 0)   -- 免费解绑，绑定体系失效
end

local UNBIND_FEE = 500
local function unbind(actor)
    if getplayvar(actor, "BIND") ~= 1 then
        sendmsg(actor, 1, "该装备非绑定状态")
        return
    end
    takeitem(actor, "金元", UNBIND_FEE, 0, "解绑费用")
    setplayvar(actor, "BIND", 0)
    sendmsg(actor, 1, "解绑成功，装备恢复可交易")
end