Refactor public network API handling and enhance connectivity checks

- Updated the public network handling to resolve the base URL dynamically based on Keystone catalog.
- Simplified the public network pool function to directly return the compute region.
- Enhanced error messages in the doctor command for better clarity on public network status.
- Introduced new functions for managing security groups and ensuring visibility of public ports in Neutron.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/test_public_net.py

@@ -1,21 +1,34 @@
-"""public-network API pool mapping and base URL."""
+"""public-network API pool = compute pool (OS_REGION_NAME)."""
 
-from gpu_rent.public_net import public_net_base, public_network_pool
+from unittest.mock import MagicMock
+
+from gpu_rent.public_net import (
+    public_net_base,
+    public_network_pool,
+    resolve_public_net_base,
+)
 
 
-def test_public_network_pool_ru6_maps_to_ru7():
-    assert public_network_pool("ru-6") == "ru-7"
-
-
-def test_public_network_pool_passthrough():
+def test_public_network_pool_is_compute_region():
+    assert public_network_pool("ru-6") == "ru-6"
     assert public_network_pool("ru-7") == "ru-7"
-    assert public_network_pool("ru-3") == "ru-3"
 
 
-def test_public_net_base_uses_public_network_path():
+def test_public_net_base_uses_compute_pool():
+    assert public_net_base("ru-6") == (
+        "https://ru-6.cloud.api.selcloud.ru/public-network"
+    )
     assert public_net_base("ru-7") == (
         "https://ru-7.cloud.api.selcloud.ru/public-network"
     )
-    assert public_net_base("ru-6") == (
-        "https://ru-7.cloud.api.selcloud.ru/public-network"
+
+
+def test_resolve_public_net_base_from_keystone_catalog():
+    conn = MagicMock()
+    conn.session.get_endpoint.return_value = (
+        "https://ru-6.cloud.api.selcloud.ru/public-network/v1/"
     )
+    assert resolve_public_net_base(conn, "ru-6") == (
+        "https://ru-6.cloud.api.selcloud.ru/public-network/v1"
+    )
+    conn.session.get_endpoint.assert_called()