add upload step

.gitea/workflows/demo.yaml

@@ -17,3 +17,40 @@ jobs:
         run: |
           ls ${{ gitea.workspace }}
       - run: echo "🍏 This job's status is ${{ job.status }}."
+  verify-artifact-upload:
+    runs-on: ubuntu-latest
+    timeout-minutes: 2
+
+    steps:
+      - name: Check out repository
+        uses: https://gitea.com/actions/checkout@v4
+        with:
+          github-server-url: https://git.nova.org
+
+      - name: Create Python environment
+        run: |
+          python3 -m venv .venv
+
+      - name: Diagnostic -- guarantee real content in test-results/
+        # Runs regardless of earlier step outcomes, so the upload step
+        # below always has something real to upload. Isolates whether
+        # gitea-upload-artifact itself works from whether the pytest step
+        # (or an earlier setup step) is what's actually failing.
+        if: always()
+        run: |
+          mkdir -p test-results
+          echo "diagnostic content $(date -u)" > test-results/diagnostic.txt
+
+      - name: Run the intentionally-failing verification test
+        run: |
+          .venv/bin/python -m pytest tests/test_zz_temp_verify_artifact_upload.py \
+            --tracing=retain-on-failure \
+            --screenshot=only-on-failure
+
+      - name: Upload failure artifacts
+        if: failure()
+        uses: https://gitea.com/actions/gitea-upload-artifact@v4
+        with:
+          name: test-results
+          path: test-results/
+          retention-days: 1