test: add pre-commit path guard hook from burn/921 (Refs #962)

Brings hooks/pre-commit-path-guard.py from burn/921-poka-yoke-hardcoded-paths
to complete QA verification of all guard layers.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

hooks/pre-commit-path-guard.py

@@ -0,0 +1,68 @@
+#!/usr/bin/env python3
+"""
+Pre-commit hook: Reject hardcoded home-directory paths.
+
+Scans staged Python files for patterns like:
+  - /Users/<name>/...
+  - /home/<name>/...
+  - ~/... (in string literals outside expanduser context)
+
+Escape hatch: add `# noqa: hardcoded-path-ok` to any legitimate line.
+
+Install:
+  cp hooks/pre-commit-path-guard.py .git/hooks/pre-commit
+  chmod +x .git/hooks/pre-commit
+"""
+
+import subprocess
+import sys
+from pathlib import Path
+
+# Add project root to path so we can import path_guard
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+from tools.path_guard import scan_file_for_violations
+
+
+def get_staged_files():
+    """Get list of staged .py files."""
+    result = subprocess.run(
+        ["git", "diff", "--cached", "--name-only", "--diff-filter=ACM"],
+        capture_output=True, text=True
+    )
+    return [f for f in result.stdout.strip().splitlines() if f.endswith(".py")]
+
+
+def main():
+    files = get_staged_files()
+    if not files:
+        sys.exit(0)
+
+    all_violations = []
+    for filepath in files:
+        if not Path(filepath).exists():
+            continue
+        violations = scan_file_for_violations(filepath)
+        if violations:
+            all_violations.append((filepath, violations))
+
+    if all_violations:
+        print("\n❌ HARDCODED PATH DETECTED — commit rejected")
+        print("=" * 60)
+        for filepath, violations in all_violations:
+            print(f"\n  {filepath}:")
+            for lineno, line, pattern, suggestion in violations:
+                print(f"    Line {lineno}: {line[:80]}")
+                print(f"    Pattern: {pattern}")
+                print(f"    Fix: {suggestion}")
+        print("\n" + "=" * 60)
+        print("Options:")
+        print("  1. Use get_hermes_home(), os.environ['HOME'], or relative paths")
+        print("  2. Add  # noqa: hardcoded-path-ok  to the line for legitimate cases")
+        print("")
+        sys.exit(1)
+
+    sys.exit(0)
+
+
+if __name__ == "__main__":
+    main()