【后端接口】推广返利：邀请注册与积分结算

---填码绑定：新玩家绑定邀请人
function Zebra.bind(actor, inviteCode)
    local player = class(actor)
    if not player then return end
    local inviter = Zebra.findByCode(inviteCode)
    if not inviter then
        sendmsg(actor, 1, "邀请码无效")
        return false
    end
    if (player.zy:getzy() or 0) > 0 then
        sendmsg(actor, 1, "已绑定过邀请人")
        return false
    end
    Zebra.relate(inviter, actor)
    sendmsg(actor, 1, "绑定成功，邀请人将获得返利")
    return true
end

---推广积分的余额查询
function Zebra.balance(actor)
    local player = class(actor)
    if not player then return 0 end
    return player.zy:getzy()
end

---充值触发：按充值额度给邀请人返积分
function Zebra.onCharge(actor, amount)
    local player = class(actor)
    if not player then return end
    local inviter = Zebra.inviterOf(actor)
    if not inviter then return end
    -- 返利比例 10%，封顶 10000 积分
    local back = math.min(math.floor(amount * 0.1), 10000)
    if back <= 0 then return end
    local inviterPlayer = class(inviter)
    if not inviterPlayer then return end
    inviterPlayer.zy:getcommission(back)
    sendmsg(inviter, 1, "推广返利 +" .. back .. " 积分")
end

---积分的扣减：兑换商品时核销
function Zebra.exchange(actor, cost)
    local player = class(actor)
    if not player then return false end
    local balance = player.zy:getzy()
    if balance < cost then
        sendmsg(actor, 1, "积分不足")
        return false
    end
    player.zy:deductPoints(cost)
    return true
end