feat: expose skip-artifact as workflow input in action.yml

action.yml:
  - Add skip-artifact input (default: 'false').
  - Forward as INPUT_SKIP_ARTIFACT env var to the PS run step.
  - Pass SkipArtifact=true to Invoke-CIJob.ps1 when set.
  - Gate 'Upload artifacts' step on inputs.skip-artifact != 'true'.

Invoke-CIJob.ps1:
  - Restore -SkipArtifact switch; skips Phase 6 and logs 'skipped' event.

Invoke-RemoteBuild.ps1:
  - Restore -SkipArtifact switch; skips packaging inside the guest.
  - Error message updated to mention skip-artifact workflow input.

scripts/Invoke-RemoteBuild.ps1

@@ -126,6 +126,10 @@ param(
     # and VMware Tools HGFS driver present in the guest.
     [switch] $UseSharedCache,
 
+    # Skip artifact packaging entirely. Use for jobs that produce no output.
+    # When absent, missing GuestArtifactSource after a successful build is an error.
+    [switch] $SkipArtifact,
+
     # Guest OS type — Linux uses SSH instead of WinRM.
     [ValidateSet('Windows', 'Linux')]
     [string] $GuestOS = 'Windows',
@@ -427,7 +431,7 @@ try {
         # ── Custom build command (e.g. python, msbuild, cmake…) ──────────
         Write-Host "[Invoke-RemoteBuild] Running build command: $BuildCommand"
         $buildExit = Invoke-Command -Session $session -ScriptBlock {
-            param($workDir, $cmd, $artifactZip, $artifactSrc, $useCache, $extraEnv)
+            param($workDir, $cmd, $artifactZip, $artifactSrc, $useCache, $extraEnv, $skipArt)
             # Unbuffered Python output — lines appear in real-time instead of being held in buffer
             $env:PYTHONUNBUFFERED = '1'
             if ($useCache) {
@@ -442,14 +446,14 @@ try {
             & cmd /c "$cmd 2>&1" | ForEach-Object { Write-Host $_ }
             $exit = $LASTEXITCODE
 
-            if ($exit -eq 0) {
+            if ($exit -eq 0 -and -not $skipArt) {
                 $archiveDir = Split-Path $artifactZip -Parent
                 if (-not (Test-Path $archiveDir)) {
                     New-Item -ItemType Directory -Path $archiveDir -Force | Out-Null
                 }
                 $srcPath = Join-Path $workDir $artifactSrc
                 if (-not (Test-Path $srcPath)) {
-                    throw "Artifact source directory not found: $srcPath. Build succeeded (exit 0) but produced no output. Check GuestArtifactSource."
+                    throw "Artifact source directory not found: $srcPath. Build succeeded (exit 0) but produced no output. Check GuestArtifactSource or set skip-artifact: 'true' in the workflow."
                 }
                 else {
                     $7zip = 'C:\Program Files\7-Zip\7z.exe'
@@ -465,7 +469,7 @@ try {
             }
 
             return $exit
-        } -ArgumentList $GuestWorkDir, $BuildCommand, $GuestArtifactZip, $GuestArtifactSource, $UseSharedCache.IsPresent, $ExtraGuestEnv
+        } -ArgumentList $GuestWorkDir, $BuildCommand, $GuestArtifactZip, $GuestArtifactSource, $UseSharedCache.IsPresent, $ExtraGuestEnv, $SkipArtifact.IsPresent
 
         if ($buildExit -ne 0) {
             throw "Build command failed (exit $buildExit)"
@@ -528,7 +532,11 @@ try {
         }
     }
 
-    Write-Host "[Invoke-RemoteBuild] Build succeeded. Artifact at $GuestArtifactZip"
+    if ($SkipArtifact) {
+        Write-Host '[Invoke-RemoteBuild] Build succeeded. Artifact packaging skipped (-SkipArtifact).'
+    } else {
+        Write-Host "[Invoke-RemoteBuild] Build succeeded. Artifact at $GuestArtifactZip"
+    }
 }
 finally {
     Remove-PSSession $session -ErrorAction SilentlyContinue