Fix demo server update workflow race condition

Add asset availability check before updating demo server. The workflow now waits
up to 5 minutes for checksums.txt and the linux-amd64 tarball to be available
before attempting the update. This prevents the install script from failing when
the release is published before all assets finish uploading.

Resolves demo server downtime during releases.

.github/workflows/update-demo-server.yml

@@ -17,6 +17,40 @@ jobs:
           echo "Prerelease: ${{ github.event.release.prerelease }}"
           echo "Updating demo server to latest stable release..."
 
+      - name: Wait for release assets
+        run: |
+          TAG="${{ github.event.release.tag_name }}"
+          echo "Waiting for release assets to be available..."
+
+          MAX_ATTEMPTS=30
+          ATTEMPT=0
+
+          while [ $ATTEMPT -lt $MAX_ATTEMPTS ]; do
+            echo "Checking for assets (attempt $((ATTEMPT + 1))/$MAX_ATTEMPTS)..."
+
+            # Check if checksums.txt and linux-amd64 tarball exist
+            CHECKSUMS_STATUS=$(curl -s -o /dev/null -w "%{http_code}" \
+              "https://github.com/rcourtman/Pulse/releases/download/${TAG}/checksums.txt")
+            TARBALL_STATUS=$(curl -s -o /dev/null -w "%{http_code}" \
+              "https://github.com/rcourtman/Pulse/releases/download/${TAG}/pulse-${TAG}-linux-amd64.tar.gz")
+
+            echo "checksums.txt: $CHECKSUMS_STATUS, tarball: $TARBALL_STATUS"
+
+            if [ "$CHECKSUMS_STATUS" = "200" ] && [ "$TARBALL_STATUS" = "200" ]; then
+              echo "✅ Release assets are available!"
+              exit 0
+            fi
+
+            ATTEMPT=$((ATTEMPT + 1))
+            if [ $ATTEMPT -lt $MAX_ATTEMPTS ]; then
+              echo "Assets not ready yet, waiting 10 seconds..."
+              sleep 10
+            fi
+          done
+
+          echo "❌ Timeout waiting for release assets"
+          exit 1
+
       - name: Setup SSH
         run: |
           mkdir -p ~/.ssh