Upgrade validation suite to Pester 6.2.0

[vartaxe]

Summary

Upgrade the repository's pinned validation toolchain from Pester 5.7.1 to Pester 6.2.0 while retaining Windows PowerShell 5.1 support. Pester 6's explicit no-fall-through mock behavior required a narrow test-only SMB mock correction; production code and the v1.0.0 release metadata remain unchanged.

Validation

• build\Invoke-Validation.ps1 passes on Windows PowerShell 5.1
• PSScriptAnalyzer returns no findings
• Pester 6.2.0 discovery and tests pass
• Full validation runs without -SkipChecksums; manifest matches worktree and candidate git archive
• Live results are recorded separately, with untested scenarios explicitly pending
• Documentation updated if behavior changed
• No credentials, internal values, or sensitive logs included

Validation command and result:

powershell.exe -NoLogo -NoProfile -ExecutionPolicy Bypass -File .\build\Invoke-Validation.ps1 -Tag v1.0.0

Passed: 140, Failed: 0, Skipped: 0, Inconclusive: 0, NotRun: 0. Pester 6.2.0, Windows PowerShell 5.1.26100.9444, PSScriptAnalyzer 1.25.0. SHA-256 manifest verified against exact source bytes.

No live ConfigMgr, WinPE, or SMB integration testing was performed.

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