fix: harden Polygon operation validation

tests/compare_test.py

@@ -10,6 +10,11 @@ compare_test.py — Polygon ↔ Nubes API (v2, трёхкатегорийная
 
 exit(1) только при BUG > 0.
 """
+if __name__ != "__main__":
+    import pytest
+
+    pytest.skip("standalone live API comparison; run explicitly with python", allow_module_level=True)
+
 import html as _html
 import os
 import sys