feat(scripting): add comprehensive scripting support for howdy monitoring

[CommitToday]

• Add howdy-monitor.sh and pamtester-monitor.sh scripts for periodic user verification
• Implement howdy_check.py Python API for programmatic authentication
• Add monitor_user.py for user presence monitoring with screen locking
• Include systemd service templates for background monitoring
• Add CLI check command for scripting integration
• Update packaging files and documentation with examples

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Closes #1055