Fix Windows CI: Add global mock for os.getloadavg

- Add conftest.py with autouse fixture to mock os.getloadavg on Windows
- Ensures all tests work on platforms without getloadavg function
- Mock only applies when getloadavg is not available (Windows)
- All existing tests continue to pass

Author: dknell

tests/conftest.py

@@ -0,0 +1,18 @@
+"""Test configuration and fixtures."""
+
+import os
+import sys
+from unittest.mock import patch
+
+import pytest
+
+
+@pytest.fixture(autouse=True)
+def mock_windows_specific_functions():
+    """Mock Windows-incompatible functions for all tests."""
+    # Only apply this mock on Windows or if getloadavg doesn't exist
+    if not hasattr(os, 'getloadavg'):
+        with patch('system_info_mcp.tools.os.getloadavg', return_value=(0.1, 0.1, 0.1)):
+            yield
+    else:
+        yield