staging deploy: load .env.staging before manage.py

infra/staging/deploy_staging.sh

@@ -25,6 +25,23 @@ cd /opt/wpp-staging/app
 runuser -u wpp -- python3 -m venv .venv
 runuser -u wpp -- .venv/bin/pip install -U pip >/dev/null
 runuser -u wpp -- .venv/bin/pip install -r requirements.txt >/dev/null
+STAGING_ENV_FILE=\"\"
+for candidate in \
+  /opt/wpp-staging/app/infra/staging/.env.staging \
+  /opt/wpp-staging/app/infra/env/.env.staging \
+  /opt/wpp-staging/.env.staging; do
+  if [ -f \"\$candidate\" ]; then
+    STAGING_ENV_FILE=\"\$candidate\"
+    break
+  fi
+done
+if [ -z \"\$STAGING_ENV_FILE\" ]; then
+  echo \"[deploy] ERROR: staging env file not found (.env.staging)\" >&2
+  exit 1
+fi
+set -a
+. \"\$STAGING_ENV_FILE\"
+set +a
 runuser -u wpp -- .venv/bin/python manage.py shell -c \"from django.conf import settings; import sys; engine = settings.DATABASES['default']['ENGINE']; print(f'DB_ENGINE={engine}'); sys.exit(0 if engine != 'django.db.backends.sqlite3' else 1)\"
 runuser -u wpp -- .venv/bin/python manage.py migrate --noinput
 systemctl restart wpp-staging.service