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.

gitea/actions/local-ci-build/action.yml

@@ -139,6 +139,15 @@ inputs:
     required: false
     default: 'false'
 
+  skip-artifact:
+    description: >
+      Set to "true" to skip artifact packaging and collection entirely.
+      Use for jobs that intentionally produce no output (lint, static analysis,
+      test-only). When absent (default), the build MUST produce artifact-source
+      or the job fails.
+    required: false
+    default: 'false'
+
 outputs:
   artifact-path:
     description: >
@@ -174,6 +183,7 @@ runs:
         INPUT_REPO_URL:              ${{ inputs.repo-url }}
         INPUT_EXTRA_GUEST_ENV_JSON:  ${{ inputs.extra-guest-env-json }}
         INPUT_USE_SHARED_CACHE:      ${{ inputs.use-shared-cache }}
+        INPUT_SKIP_ARTIFACT:         ${{ inputs.skip-artifact }}
       run: |
         #Requires -Version 5.1
         Set-StrictMode -Version Latest
@@ -254,9 +264,10 @@ runs:
             Configuration       = $env:INPUT_CONFIGURATION
         }
 
-        if ($env:INPUT_SUBMODULES    -eq 'true') { $params['Submodules']    = $true }
+        if ($env:INPUT_SUBMODULES       -eq 'true') { $params['Submodules']    = $true }
         if ($env:INPUT_USE_GIT_CLONE    -eq 'true') { $params['UseGitClone']    = $true }
         if ($env:INPUT_USE_SHARED_CACHE -eq 'true') { $params['UseSharedCache'] = $true }
+        if ($env:INPUT_SKIP_ARTIFACT    -eq 'true') { $params['SkipArtifact']   = $true }
         if ($resolvedTemplatePath)                   { $params['TemplatePath']   = $resolvedTemplatePath }
         if ($resolvedSnapshotName)                { $params['SnapshotName']  = $resolvedSnapshotName }
         if ($extraGuestEnv.Count -gt 0)           { $params['ExtraGuestEnv'] = $extraGuestEnv }
@@ -270,7 +281,7 @@ runs:
 
     # ── Upload build artifacts on success ─────────────────────────────────────
     - name: Upload artifacts
-      if: success()
+      if: success() && inputs.skip-artifact != 'true'
       uses: actions/upload-artifact@v4
       with:
         name: ${{ steps.invoke-ci.outputs.artifact-name }}