Isolate cloud model access before enabling product RAG workflows

The API and ingestion tools now use a fixed internal model gateway while
governed profiles, embedding cache assignments, traceable citations, and
stable API errors establish the boundaries required by later workflows.

Constraint: The current Alibaba Cloud workspace rejects all three live model calls with authentication failures
Rejected: Give the API or seed tools the Bailian key and direct egress | combines database access, cloud credentials, and public network access
Rejected: Mix offline and Bailian vectors in one demo namespace | makes profile activation and retrieval ambiguous
Confidence: high
Scope-risk: moderate
Reversibility: clean
Directive: Keep Bailian credentials and egress exclusive to model-gateway and create a new immutable profile hash for any embedding identity change
Tested: make verify; 121 backend tests; 14 frontend tests; fresh and populated Alembic upgrade-downgrade-upgrade; two idempotent offline seeds; Docker health and HTTP retrieval; isolated provider smoke
Not-tested: Successful live Bailian responses because the supplied workspace credential currently fails authentication

.env.example

@@ -16,6 +16,11 @@ POSTGRES_APP_PASSWORD_FILE=/run/secrets/postgres_app_password
 UPLOAD_ROOT=/data/uploads
 MAX_UPLOAD_MB=100
 
+MODEL_GATEWAY_BASE_URL=http://model-gateway:8000
+MODEL_GATEWAY_TOKEN_FILE=/run/secrets/model_gateway_api_token
+MODEL_GATEWAY_CALLER=api
+MODEL_GATEWAY_TIMEOUT_SECONDS=120
+
 # The actual workspace host is local deployment configuration and is not committed.
 BAILIAN_OPENAI_BASE_URL=https://<workspace-id>.cn-beijing.maas.aliyuncs.com/compatible-mode/v1
 BAILIAN_NATIVE_BASE_URL=https://<workspace-id>.cn-beijing.maas.aliyuncs.com/api/v1