feat: add Docker MTU apply support and docker-ordered persistence

https://chatgpt.com/share/69733e45-96ec-800f-9aad-0cac7306dedd

tests/unit/test_net.py

@@ -1,4 +1,5 @@
 import unittest
+from pathlib import Path
 from unittest.mock import patch
 
 import automtu.net as net
@@ -44,6 +45,20 @@ class TestNet(unittest.TestCase):
             self.assertTrue(net.default_route_uses_iface("eth0"))
             self.assertFalse(net.default_route_uses_iface("wg0"))
 
+    def test_list_ifaces_returns_sorted_names(self) -> None:
+        fake = [
+            Path("/sys/class/net/eth0"),
+            Path("/sys/class/net/lo"),
+            Path("/sys/class/net/wg0"),
+        ]
+
+        with (
+            patch("automtu.net.pathlib.Path.exists", return_value=True),
+            patch("automtu.net.pathlib.Path.iterdir", return_value=fake),
+            patch.object(Path, "is_dir", return_value=True),
+        ):
+            self.assertEqual(net.list_ifaces(), ["eth0", "lo", "wg0"])
+
 
 if __name__ == "__main__":
     unittest.main(verbosity=2)