Carried verbatim in Phase 2 so the methodology repo's test suite
(tests/test_parallel_determinism.py and the Phase-7 validation drivers)
runs unchanged. _parallel.py is the process-pool helper; run_*.py are
the SBC / coverage / sparcnet-retest / gold-chain / phase1 / phase4
drivers re-run in Phase 7.
NOTE: build_unified_labels.py and consolidate_label_tiers.py are
deliberately NOT here — their canonical, Phase-1-corrected copies live
in pipeline/ (build_unified_labels.py path-patched; consolidate_label_tiers.py
R3-corrected to avoid Centaur double-count). Do not re-introduce the
methodology-repo originals here (divergent-copy hazard).