Add daily backup workflow for Neon database

.github/workflows/neon-backup.yml

@@ -0,0 +1,38 @@
+name: Daily Neon Database Backup
+
+on:
+  schedule:
+    # Elke nacht om 02:00 UTC = 04:00 Nederlandse zomertijd / 03:00 wintertijd
+    - cron: "0 2 * * *"
+
+  # Hiermee kun je handmatig testen via GitHub
+  workflow_dispatch:
+
+jobs:
+  backup:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Install PostgreSQL client
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y postgresql-client
+
+      - name: Create backup
+        env:
+          DATABASE_URL: ${{ secrets.NEON_DATABASE_URL }}
+        run: |
+          mkdir -p backups
+          DATE=$(date +"%Y-%m-%d_%H-%M-%S")
+          pg_dump "$DATABASE_URL" \
+            --format=custom \
+            --no-owner \
+            --no-privileges \
+            --file="backups/neon-backup-$DATE.dump"
+
+      - name: Upload backup artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: neon-database-backup
+          path: backups/*.dump
+          retention-days: 30