Refactor PowerShell SCCM maintenance and CI coverage

[cgfixit]

Summary

• Refactor sccmpatch.ps1 into a testable PowerShell 5.1-compatible orchestration flow.
• Preserve and exercise SCCM exit codes, including reachable invalid-stage 90, timeout 30, reboot 3010, and guarded failure mappings.
• Add explicit terminating behavior for Veeam/WinRM service operations and native ShouldProcess/-WhatIf protection.
• Add mocked unit coverage and a process-level integration test.
• Run parser and Pester validation on Ubuntu PowerShell 7 and Windows PowerShell 5.1 in CI.

Validation

• Windows PowerShell 5.1 parser: PASS
• Pester 5.8.0: 17/17 PASS
• Workflow YAML parse: PASS
• No live Veeam, WinRM, SCCM, or proxy operations performed
• Local PSScriptAnalyzer/actionlint unavailable; GitHub Actions provides those checks

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None