feat(tools): add check-frontmatter.py - first coherence tool

tools/coherence/check-frontmatter.py

@@ -0,0 +1,60 @@
+#!/usr/bin/env python3
+"""
+check-frontmatter.py - Validates markdown files have frontmatter
+
+One thing: Check if files have YAML frontmatter.
+"""
+
+import sys
+import yaml
+from pathlib import Path
+
+def has_frontmatter(filepath):
+    """Check if file has YAML frontmatter."""
+    try:
+        with open(filepath, "r", encoding="utf-8") as f:
+            content = f.read()
+            if content.startswith("---"):
+                parts = content.split("---", 3)
+                if len(parts) >= 3:
+                    yaml.safe_load(parts[1])
+                    return True
+    except Exception:
+        pass
+    return False
+
+def main():
+    """Check markdown files for frontmatter."""
+    path_arg = sys.argv[1] if len(sys.argv) > 1 else "."
+    
+    issues = []
+    checked = 0
+    path = Path(path_arg)
+    
+    if path.is_file() and path.suffix == ".md":
+        checked = 1
+        if not has_frontmatter(path):
+            issues.append(str(path))
+    elif path.is_dir():
+        for filepath in path.rglob("*.md"):
+            checked += 1
+            if not has_frontmatter(filepath):
+                issues.append(str(filepath))
+    else:
+        print(f"Error: {path_arg} is not a file or directory")
+        sys.exit(2)
+    
+    print(f"Checked: {checked}")
+    print(f"Missing frontmatter: {len(issues)}")
+    
+    if issues:
+        print("\nFiles missing frontmatter:")
+        for issue in issues:
+            print(f"  {issue}")
+        sys.exit(1)
+    else:
+        print("All files have frontmatter. OK")
+        sys.exit(0)
+
+if __name__ == "__main__":
+    main()