test: add python validator heading detection

scripts/tests/test_validate_skills_headings.py

@@ -0,0 +1,18 @@
+import os
+import sys
+
+sys.path.append(os.path.dirname(os.path.dirname(__file__)))
+from validate_skills import has_when_to_use_section
+
+SAMPLES = [
+    ("## When to Use", True),
+    ("## Use this skill when", True),
+    ("## When to Use This Skill", True),
+    ("## Overview", False),
+]
+
+for heading, expected in SAMPLES:
+    content = f"\n{heading}\n- item\n"
+    assert has_when_to_use_section(content) is expected, heading
+
+print("ok")