devops: fix staging deploy archive URL fetch (refs #20 #23)

infra/staging/deploy_staging.sh

@@ -11,7 +11,7 @@ echo "[deploy] extracting source + installing deps + migrate + restart"
 sudo -n pct exec "${CT_ID}" -- bash -lc "set -euo pipefail
 mkdir -p /opt/wpp-staging/releases/src
 cd /opt/wpp-staging/releases
-curl -fsSL -o app.tar.gz 
+curl -fsSL "${ARCHIVE_URL}" -o app.tar.gz
 rm -rf src && mkdir src
 tar -xzf app.tar.gz -C src --strip-components=1
 rm -rf /opt/wpp-staging/app/*