ci(nightly): archive receipts without upload-artifact@v4

Gitea act_runner rejects artifact v4; host runner now has curl/node via brew+host net.

Co-authored-by: Cursor <cursoragent@cursor.com>

.github/workflows/nightly-real-pi.yml

@@ -49,16 +49,24 @@ jobs:
           # Always upload receipts/evidence; never treat missing secret as PASS.
           exit "${rc}"
 
-      - name: Upload promotion receipt artifacts
+      # Gitea act_runner rejects upload-artifact@v4 (GHESNotSupportedError).
+      # Keep a portable tarball in the job log workspace for local runner hosts.
+      - name: Archive promotion receipt artifacts
         if: always()
-        uses: actions/upload-artifact@v4
-        with:
-          name: promotion-receipt-${{ github.sha }}
-          path: |
-            .doc/test-reports/assets/promotion-receipts/${{ github.sha }}.json
-            .doc/test-reports/assets/promotion-receipts/evidence-*
-          if-no-files-found: warn
-          retention-days: 14
+        run: |
+          set -euo pipefail
+          out="promotion-receipt-${GITHUB_SHA}.tar.gz"
+          mkdir -p .doc/test-reports/assets/promotion-receipts
+          if compgen -G ".doc/test-reports/assets/promotion-receipts/${GITHUB_SHA}.json" >/dev/null \
+            || compgen -G ".doc/test-reports/assets/promotion-receipts/evidence-*" >/dev/null; then
+            tar -czf "${out}" \
+              .doc/test-reports/assets/promotion-receipts/"${GITHUB_SHA}".json \
+              .doc/test-reports/assets/promotion-receipts/evidence-* \
+              2>/dev/null || tar -czf "${out}" .doc/test-reports/assets/promotion-receipts
+            ls -la "${out}"
+          else
+            echo "warn: no promotion receipt files to archive"
+          fi
 
       - name: Summarize receipt verdict
         if: always()