feat(sprint4-6): quality, reliability, perf baseline

Sprint 4 — qualità codice:
- scripts/_Common.psm1: New-CISessionOption, Resolve-VmrunPath, Invoke-Vmrun
- PSScriptAnalyzerSettings.psd1: project-wide PSSA rules (security + formatting)
- Remove-BuildVM.ps1: SupportsShouldProcess (-WhatIf support)
- Invoke-RemoteBuild.ps1, Get-BuildArtifacts.ps1: use New-CISessionOption from module
- New-BuildVM.ps1: use Resolve-VmrunPath + Invoke-Vmrun from module

Sprint 5 — affidabilità:
- Backup-CITemplate.ps1: stop runner, timestamped VMDK backup, prune old, restart
- Watch-RunnerHealth.ps1: auto-restart act_runner, cooldown 3/h, EventLog + webhook
- Register-CIScheduledTasks.ps1: add CI-RunnerHealth task (every 15 min)

Sprint 6 — perf baseline:
- Set-TemplateSharedFolders.ps1: idempotent VMX editor for NuGet/pip shared folders
- Invoke-RemoteBuild.ps1: -UseSharedCache injects NUGET_PACKAGES + PIP_CACHE_DIR in guest
- Measure-CIBenchmark.ps1: times clone/start/IP/WinRM/destroy, appends to benchmark.jsonl

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/Get-BuildArtifacts.ps1

@@ -57,13 +57,15 @@ param(
 Set-StrictMode -Version Latest
 $ErrorActionPreference = 'Stop'
 
+Import-Module (Join-Path $PSScriptRoot '_Common.psm1') -Force
+
 # Ensure destination exists on host
 if (-not (Test-Path $HostArtifactDir)) {
     New-Item -ItemType Directory -Path $HostArtifactDir -Force | Out-Null
     Write-Host "[Get-BuildArtifacts] Created host artifact directory: $HostArtifactDir"
 }
 
-$sessionOptions = New-PSSessionOption -SkipCACheck -SkipCNCheck -SkipRevocationCheck
+$sessionOptions = New-CISessionOption
 
 Write-Host "[Get-BuildArtifacts] Connecting to VM at $IPAddress..."
 $session = New-PSSession `