[CRITICAL] argparse.parse_args() called twice - Flask crash on startup

## Description\n`args = parser.parse_args()` is called at module level AND inside `if __name__ == '__main__'`. When run via `flask run` or gunicorn, crashes with `unrecognized arguments` error.\n\n## Severity\nCritical\n\n## File\nBackend/app.py, lines 21-23 and 235-239\n\n## Fix\nMove parse_args() inside `if __name__ == '__main__'` block only.