高温氦气物性补全；三通四通能量计算bug修正

tests/test_amesim_pnch012_component.py

@@ -1,3 +1,8 @@
+"""Legacy Python-kernel test placeholder; contains no executable test cases.
+
+PNCH012 execution is covered by test_amesim_pnch012_xml,
+test_native_node_conservation, and test_native_catalog after C migration.
+"""
 from __future__ import annotations
 
 import unittest