Fix linting: use builtin OSError and TimeoutError instead of socket aliases

tests/unit/test_transport.py

@@ -64,7 +64,7 @@ class TestTCPTransport:
         """Test connection failure raises ConnectionError."""
         mock_sock = MagicMock()
         mock_socket_class.return_value = mock_sock
-        mock_sock.connect.side_effect = socket.error("Connection refused")
+        mock_sock.connect.side_effect = OSError("Connection refused")
 
         with pytest.raises(ConnectionError, match="Failed to connect"):
             transport.connect()
@@ -113,7 +113,7 @@ class TestTCPTransport:
         """Test write failure raises IOError."""
         mock_sock = MagicMock()
         mock_socket_class.return_value = mock_sock
-        mock_sock.sendall.side_effect = socket.error("Write failed")
+        mock_sock.sendall.side_effect = OSError("Write failed")
 
         transport.connect()
 
@@ -167,7 +167,7 @@ class TestTCPTransport:
         """Test read timeout raises TimeoutError."""
         mock_sock = MagicMock()
         mock_socket_class.return_value = mock_sock
-        mock_sock.recv.side_effect = socket.timeout("Timed out")
+        mock_sock.recv.side_effect = TimeoutError("Timed out")
 
         transport.connect()