PASS ruff check util/cross_worker_context.py util/qf_bv_backend.py
     util/query_store.py util/symcc_query_service.py
     benchmark/check_cross_worker_context_oracles.py
     test/test_cross_worker_context.py test/test_qf_bv_backend.py
PASS python3 -m py_compile on the same production/oracle/test modules
PASS git diff --check
PASS SVG parses as 1600x960 and PNG renders as 2000x1200
PASS visual inspection: labels render, arrows connect intended stages, no overlap