src/jira_to_code/tasks/medium/formatter.py

def format_user_data(user_dict):
    """
    Takes a dictionary with 'first_name', 'last_name', and 'age'.
    Should return a string formatted exactly like: "LAST_NAME, First_name (Age: X)"
    If 'age' is missing, it should default to "Unknown".
    """
    pass # TODO: Implement this function based on the docstring