refactor(workflow): enhance SSH setup and cleanup logic

[warnyul]

• Reorganized the workflow to improve clarity and maintainability:
  • Added a new noop.sh script for setup post-check of known hosts.
  • Moved the Setup SSH key step after Check known hosts file for better sequence.
• Improved the check.sh script:
  • Validates the presence of expected SSH fingerprints in the known_hosts file.
• Updated the post_action.sh script:
  • Simplified removal of the known_hosts file instead of line-by-line cleanup.
• Adjusted post_check.sh to ensure the known_hosts file is completely removed.
• Updated action.yml to include corrected paths and a reordering of the steps.