Re-add JitPack trigger to CI workflow

- Trigger main-SNAPSHOT builds on main branch pushes
- Only runs after tests pass (needs: test)
- Keeps main-SNAPSHOT available for consumers
- Fire-and-forget approach - won't fail CI if JitPack has issues

Author: wassertim

.github/workflows/ci.yml

@@ -33,4 +33,16 @@ jobs:
     - name: Test integration tests
       run: |
         cd integration-tests
-        mvn clean test
+        mvn clean test
+
+  jitpack-trigger:
+    runs-on: ubuntu-latest
+    if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+    needs: test
+
+    steps:
+    - name: Trigger JitPack build for main branch
+      run: |
+        echo "🚀 Triggering JitPack build for main-SNAPSHOT"
+        curl -s "https://jitpack.io/com/github/wassertim/dynamodb-toolkit/main-SNAPSHOT" || true
+        echo "✅ JitPack build triggered for main-SNAPSHOT"