fix: restart SeaweedFS services before downloading files on test failure

Problem: --abort-on-container-exit stops ALL containers when tests
fail, so SeaweedFS services are down when file download step runs.

Solution:
1. Use continue-on-error: true to capture test failure
2. Store exit code in GITHUB_OUTPUT for later checking
3. Add new step to restart SeaweedFS services if tests failed
4. Download step runs after services are back up
5. Final step checks test exit code and fails workflow

This ensures:
✅ Services keep running for file analysis
✅ Parquet files are accessible via filer API
✅ Workflow still fails if tests failed
✅ All diagnostics can complete

Now we'll actually be able to download and examine the Parquet files!

.github/workflows/spark-integration-tests.yml

@@ -120,13 +120,34 @@ jobs:
 
     - name: Run Spark integration tests
       working-directory: test/java/spark
+      continue-on-error: true
+      id: test-run
       run: |
         echo "=== Running Spark Integration Tests ==="
         docker compose up --abort-on-container-exit --exit-code-from spark-tests spark-tests
-        echo "✓ Tests completed"
+        TEST_EXIT_CODE=$?
+        echo "exit_code=$TEST_EXIT_CODE" >> $GITHUB_OUTPUT
+        echo "Tests completed with exit code: $TEST_EXIT_CODE"
+        exit $TEST_EXIT_CODE
+
+    - name: Restart SeaweedFS services for file download
+      if: steps.test-run.outcome == 'failure'
+      working-directory: test/java/spark
+      run: |
+        echo "=== Restarting SeaweedFS services to access files ==="
+        docker compose up -d seaweedfs-master seaweedfs-volume seaweedfs-filer
+        
+        echo "Waiting for filer to be ready..."
+        for i in {1..10}; do
+          if curl -f http://localhost:8888/ > /dev/null 2>&1; then
+            echo "✓ Filer is ready"
+            break
+          fi
+          sleep 2
+        done
 
     - name: Download and examine Parquet files
-      if: failure()
+      if: steps.test-run.outcome == 'failure'
       working-directory: test/java/spark
       run: |
         echo "=== Downloading Parquet files for analysis ==="
@@ -221,6 +242,13 @@ jobs:
         reporter: java-junit
         fail-on-error: true
 
+    - name: Check test results
+      if: steps.test-run.outcome == 'failure'
+      run: |
+        echo "❌ Tests failed with exit code: ${{ steps.test-run.outputs.exit_code }}"
+        echo "But file analysis was completed above."
+        exit 1
+
     # ========================================
     # SPARK EXAMPLE (HOST-BASED)
     # ========================================