refactor(ci): drop upload/download-artifact (remove github.com dependency)

actions/upload-artifact and download-artifact run code fetched from
github.com (and v4 is GHES-incompatible, v3 deprecated). The runner
host is single with a shared filesystem, so the orchestrator's
host-side collect dir is the artifact handoff:

- action.yml: replace the two upload-artifact steps with
  host-path report steps; artifacts stay under F:\CI\Artifacts and
  are aged by Invoke-RetentionPolicy.ps1.
- build-nsInnoUnp.yml: release job reads
  F:\CI\Artifacts\{run_id}-{run_attempt}-{target} directly instead of
  download-artifact; existing Gitea REST release-asset upload unchanged.

Tradeoff (accepted): artifacts are no longer downloadable from the
Gitea Actions run page for non-tag builds — only on host disk, and as
release assets for tagged builds.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

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

@@ -98,7 +98,12 @@ inputs:
     default: ''
 
   artifact-retention-days:
-    description: 'Days to retain uploaded artifacts in Gitea.'
+    description: >
+      Deprecated / no-op. Artifacts are no longer uploaded to the Gitea
+      Actions store (that needs the github.com-hosted upload-artifact
+      action). They stay on the host under F:\CI\Artifacts and are aged
+      out by scripts/Invoke-RetentionPolicy.ps1. Kept for caller
+      back-compat.
     required: false
     default: '14'
 
@@ -287,22 +292,34 @@ runs:
         [System.IO.File]::AppendAllText(
             $env:GITHUB_OUTPUT, "artifact-name=$artifactName`n", $utf8NoBom)
 
-    # ── Upload build artifacts on success ─────────────────────────────────────
-    - name: Upload artifacts
+    # ── Report artifact location ──────────────────────────────────────────────
+    # No actions/upload-artifact: that action's code is fetched from
+    # github.com (and v4 is GHES-incompatible, v3 deprecated). The runner
+    # host is single and its filesystem is shared across jobs, so the
+    # orchestrator's host-side collect dir IS the artifact handoff.
+    # Downstream jobs read F:\CI\Artifacts\{run_id}-{run_attempt}[-suffix]
+    # directly (see build-nsInnoUnp.yml release job).
+    - name: Report artifact location
       if: success() && inputs.skip-artifact != 'true'
-      uses: actions/upload-artifact@v3
-      with:
-        name: ${{ steps.invoke-ci.outputs.artifact-name }}
-        path: ${{ steps.invoke-ci.outputs.artifact-path }}
-        retention-days: ${{ inputs.artifact-retention-days }}
-        if-no-files-found: error
+      shell: powershell
+      run: |
+        $p = '${{ steps.invoke-ci.outputs.artifact-path }}'
+        if (-not (Test-Path -LiteralPath $p) -or
+            -not (Get-ChildItem -Force -LiteralPath $p)) {
+            throw "no artifacts at $p"
+        }
+        Write-Host "Artifacts on host: $p"
+        Get-ChildItem -Recurse -File -LiteralPath $p |
+            ForEach-Object { Write-Host "  $($_.FullName)" }
 
-    # ── Upload diagnostic logs on failure ─────────────────────────────────────
-    - name: Upload diagnostic logs on failure
+    - name: Report diagnostic log location on failure
       if: failure()
-      uses: actions/upload-artifact@v3
-      with:
-        name: build-logs-${{ github.sha }}
-        path: ${{ steps.invoke-ci.outputs.artifact-path }}/*.log
-        retention-days: 3
-        if-no-files-found: ignore
+      shell: powershell
+      run: |
+        $p = '${{ steps.invoke-ci.outputs.artifact-path }}'
+        if ($p -and (Test-Path -LiteralPath $p)) {
+            Write-Host "Diagnostic logs (if any) on host: $p"
+            Get-ChildItem -Recurse -File -Filter '*.log' -LiteralPath $p `
+                -ErrorAction SilentlyContinue |
+                ForEach-Object { Write-Host "  $($_.FullName)" }
+        }