Persistent keepalive and listen port are not surfaced in stats on macos

```
select * from location_stats order by id desc;
+-------+-------------+---------+-----------+----------------+----------------------------+-------------+-------------------------------+
| id | location_id | upload | download | last_handshake | collected_at | listen_port | persistent_keepalive_interval |
+-------+-------------+---------+-----------+----------------+----------------------------+-------------+-------------------------------+
| 97640 | 3 | 3788 | 7545 | 1782143060 | 2026-06-22 15:46:19.852847 | 0 | |
| 97639 | 3 | 3788 | 7545 | 1782143060 | 2026-06-22 15:46:09.849103 | 0 | |
| 97638 | 3 | 3788 | 7545 | 1782143060 | 2026-06-22 15:45:59.850417 | 0 | |
| 97637 | 3 | 3788 | 7545 | 1782143060 | 2026-06-22 15:45:49.847826 | 0 | |
| 97636 | 3 | 3672 | 7397 | 1782143060 | 2026-06-22 15:45:39.847735 | 0 | |
| 97635 | 3 | 3672 | 7397 | 1782143060 | 2026-06-22 15:45:29.849417 | 0 | |
| 97634 | 3 | 3672 | 7397 | 1782143060 | 2026-06-22 15:45:19.849735 | 0 | |
| 97633 | 3 | 3672 | 7397 | 1782143060 | 2026-06-22 15:45:09.849156 | 0 | |
| 97632 | 3 | 3672 | 7397 | 1782143060 | 2026-06-22 15:44:59.849036 | 0 | |
| 97631 | 3 | 3412 | 7037 | 1782143060 | 2026-06-22 15:44:49.848993 | 0 | |
```

Hint: Keepalive can be taken from settings.

Check how to get listening port in VPNExtension and inform the main app about it.