fix: remove duplicate logging.shutdown() call

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: anticomputer

src/seclab_taskflow_agent/cli.py

@@ -180,7 +180,6 @@ def main(
     logging.shutdown()
     sys.stdout.flush()
     sys.stderr.flush()
-    logging.shutdown()
     os._exit(exit_code)