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/Remove-BuildVM.ps1

@@ -25,7 +25,7 @@
 .EXAMPLE
     .\Remove-BuildVM.ps1 -VMPath "F:\CI\BuildVMs\Clone_run-42_20260508_143022\Clone_run-42_20260508_143022.vmx"
 #>
-[CmdletBinding()]
+[CmdletBinding(SupportsShouldProcess)]
 param(
     [Parameter(Mandatory)]
     [string] $VMPath,
@@ -47,12 +47,14 @@ Write-Host "[Remove-BuildVM] Destroying VM: $VMPath"
 if (-not (Test-Path $VMPath -PathType Leaf)) {
     Write-Warning "[Remove-BuildVM] VMX file not found — nothing to remove: $VMPath"
     # Still attempt to remove the directory in case of partial clone
-    if (Test-Path $cloneDir) {
+    if ((Test-Path $cloneDir) -and $PSCmdlet.ShouldProcess($cloneDir, 'Remove partial clone directory')) {
         Remove-Item $cloneDir -Recurse -Force -ErrorAction SilentlyContinue
     }
     return
 }
 
+if (-not $PSCmdlet.ShouldProcess($VMPath, 'Stop and delete build VM')) { return }
+
 # ── Step 2: Graceful stop ─────────────────────────────────────────────────────
 Write-Host "[Remove-BuildVM] Sending soft stop..."
 & $VmrunPath -T ws stop $VMPath soft 2>&1 | Out-Null