fix: run module subprocess exit properly on failing

[Revathyvenugopal162]

fix #591

output preview

(.venv) PS > python .\dyna_without_input.py
LS-DYNA completed with warnings or errors in the log.
Check the log file for details: <folder_name>\lsrun.out.txt

Additional info

• The original subprocess.run() approach was unreliable in detecting LS-DYNA run failures because it used stderr=subprocess.PIPE, causing CalledProcessError.stderr to be None. This made it hard to capture and propagate meaningful error information.LS-DYNA doesn't print to stdout, so Popen(..., stdout=PIPE) just hangs.
• Additionally, since LS-DYNA execution is long-running, a blocking subprocess call without feedback caused misleading behavior in long runs and potential hangs.
• The script now uses subprocess.Popen() combined with polling to monitor lsrun.out.txt for errors/warnings, providing real-time detection and logging