CI demo build (#1040)

.github/workflows/demo.yml

@@ -0,0 +1,25 @@
+name: Demo
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+    paths:
+      - 'demo/**'
+  release:
+    types: [ published ]
+  workflow_dispatch:
+
+jobs:
+  demo:
+    name: Demo
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v4
+
+      - run: |
+          cd demo/frontend
+          docker-compose build