chinext50_regime_project research project.chinext50_regime_build_handoff_2026-04-08.md as reference baseline.chinext50_regime_review_2026-04-09.md and a concrete improvement plan before the next implementation round.chinext50_blocker_checklist_for_codex.md in B1 -> B6 order under OpenSpec flow, with per-blocker file/test/metric reporting and no threshold/policy tuning before B1-B5 completion.chinext50_post_b3_feedback_response_for_codex_2026-04-10.md in sequence: D0 -> preparatory repair-threshold code change -> H1b.1-L1 -> L2 -> L3 -> if all fail then H1b.2-direct-from-R1.