ci: move validate maintainers logic to lib

Allow easily running the individual checks outside of GHA for easier
testing/modification.

Signed-off-by: Austin Horstman <khaneliman12@gmail.com>

lib/python/validate-maintainers-syntax.py

@@ -0,0 +1,25 @@
+#!/usr/bin/env python3
+"""
+Validate maintainers.nix syntax
+
+This script validates that the maintainers.nix file has valid Nix syntax.
+"""
+
+import subprocess
+import sys
+
+
+def main():
+    print("🔍 Validating maintainers.nix syntax...")
+
+    try:
+        subprocess.run(['nix', 'eval', '--file', 'modules/lib/maintainers.nix', '--json'],
+                               capture_output=True, text=True, check=True)
+        print("✅ Valid Nix syntax")
+    except subprocess.CalledProcessError:
+        print("❌ Invalid Nix syntax")
+        sys.exit(1)
+
+
+if __name__ == "__main__":
+    main()