add SEED_ADMIN_PASSWORD environment variable to backend service

docker-compose.prod.yml

@@ -21,6 +21,7 @@ services:
     environment:
       DATABASE_URL: postgres://${POSTGRES_USER}:${POSTGRES_PASSWORD}@postgres:5432/${POSTGRES_DB}?sslmode=disable
       JWT_SECRET: ${JWT_SECRET}
+      SEED_ADMIN_PASSWORD: ${SEED_ADMIN_PASSWORD}
     # Нет expose - backend доступен только внутри сети delivery-network
     depends_on:
       postgres: