Install teamhub-document-recognition-engine v0.1.0 in the backend CI job through the ENGINES_TOKEN PAT (git insteadOf rewrite, --no-deps plus pdfminer.six, pin matches app/ingestion/ENGINE_SOURCE.md). The step fails with a clear error when the secret is missing. test_chunker.py and the engine adapter tests now run for real in CI instead of skipping. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>