Github actions: frontend build

.github/workflows/frontend-build.yml

@@ -0,0 +1,42 @@
+name: Frontend Build
+
+on:
+  push:
+    branches: [ main ]
+    paths:
+      - 'frontend/**'
+  pull_request:
+    branches: [ main ]
+    paths:
+      - 'frontend/**'
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Node.js
+      uses: actions/setup-node@v4
+      with:
+        node-version: '22'
+        cache: 'npm'
+        cache-dependency-path: frontend/package-lock.json
+
+    - name: Install dependencies
+      run: npm ci
+      working-directory: ./frontend
+
+    - name: Build frontend
+      run: npm run build
+      working-directory: ./frontend
+      env:
+        NODE_ENV: production
+
+    - name: Archive production artifacts
+      uses: actions/upload-artifact@v4
+      with:
+        name: frontend-build
+        path: frontend/public
+        retention-days: 5