feat: enhance mock database store with context manager support and improve cursor behavior

tests/unit/test_config_e2e.py

@@ -12,7 +12,14 @@ def test_end_to_end_config_workflow():
     """Test complete configuration workflow."""
     # Create mocks
     settings = Mock(spec=Settings)
+    cursor = Mock()
+    cursor.fetchone.return_value = None
+    cursor.fetchall.return_value = []
+    cursor.execute.return_value = cursor
+    context = Mock()
+    context.__enter__.return_value = cursor
     store = Mock(spec=DuckDBStore)
+    store.connect.return_value = context
     audit_repo = Mock(spec=AuditRepository)
 
     # Create service