fix: 解决 UFW 防火墙添加端口备注时不生效的问题 (#2491)

Refs #2487

backend/app/service/firewall.go

@@ -241,6 +241,9 @@ func (u *FirewallService) OperatePortRule(req dto.PortRuleOperate, reload bool)
 			if err := u.operatePort(client, req); err != nil {
 				global.LOG.Errorf("%s port %s/%s failed (strategy: %s, address: %s), err: %v", req.Operation, req.Port, req.Protocol, req.Strategy, req.Address, err)
 			}
+			if len(req.Protocol) == 0 {
+				req.Protocol = "tcp/udp"
+			}
 			_ = u.addPortRecord(req)
 		}
 		return nil