feat(task-019): add deterministic end-to-end demo stack flow

docker-compose.yml

@@ -18,6 +18,8 @@ services:
       context: .
       dockerfile: apps/backend/Dockerfile
     environment:
+      PIPELINE_DEMO_MODE: "1"
+      PIPELINE_DEMO_PUBLISH_REPO_PATH: /demo/pipeline-demo-site.git
       POSTGRES_DSN: postgresql://${POSTGRES_USER:-pipeline}:${POSTGRES_PASSWORD:-pipeline_local}@postgres:5432/${POSTGRES_DB:-pipeline}
       REDIS_URL: redis://redis:6379/0
       OBJECT_STORAGE_ENDPOINT: http://minio:9000
@@ -25,6 +27,8 @@ services:
       OBJECT_STORAGE_SECRET_ACCESS_KEY: ${MINIO_ROOT_PASSWORD:-minio_local_password}
       OBJECT_STORAGE_BUCKET: ${OBJECT_STORAGE_BUCKET:-pipeline-local}
       OBJECT_STORAGE_REGION: ${OBJECT_STORAGE_REGION:-us-east-1}
+    volumes:
+      - demo-publish-repo:/demo
     ports:
       - "${BACKEND_PORT:-8000}:8000"
     depends_on:
@@ -109,3 +113,4 @@ volumes:
   postgres-data:
   redis-data:
   minio-data:
+  demo-publish-repo: