feat(infra) : ajout maintenance mode nginx-proxy + extraction maintenance.html au deploy

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

infra/prod/deploy.sh

@@ -20,6 +20,10 @@ sudo docker compose up -d
 echo "==> Waiting for container to be ready..."
 sleep 3
 
+echo "==> Extracting maintenance page..."
+mkdir -p public
+sudo docker compose cp app:/var/www/html/public/maintenance.html public/maintenance.html
+
 echo "==> Running migrations..."
 sudo docker compose exec -T -u www-data app php bin/console doctrine:migrations:migrate --no-interaction