Once retrieval_promise_gate.py imports customer_copy_vocab and drops its STEMS literal, the drift
check reads "ok — single source" instead of failing on the missing literal. An import only in a
comment, or beside a stale literal, is still drift. Pinned by scripts/test_hub_copy_drift.py.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS
