Updated process_month to remove empty monthly data files

            newly_added_count = len(unique_rows) - len(existing_test_data)

            rows_moved += newly_added_count

            print(f"  {src_path.name}: moved {newly_added_count} new rows to {test_path.name}. Total test rows: {len(unique_rows)}")

            if not remaining_src_rows:

                os.remove(src_path)

                print(f"  Removed empty source file: {src_path.name}")

    return files_processed, rows_moved

# ---------------------------- Core logic: Revert ---------------------------------