docs: reset mitc4 formulation baseline

PROGRESS.md

@@ -13,10 +13,42 @@ Every new agent session must read this file together with `PLAN.md` before plann
 - Do not remove history unless the user explicitly asks for archival cleanup.
 
 ## Current Status
-P1-01 through P1-14 have an initial C++17 implementation with CMake/CTest validation. P1-15 and P1-16 remain blocked because the repository does not yet contain a Phase 1-compatible Abaqus `TYPE=S4` input with matching `*_displacements.csv`; the first stored pair remains `quad_01.inp` and `quad_01_displacements.csv`, with `quad_01.inp` documented as S4R/NLGEOM provenance rather than Phase 1 parser input.
+Phase 1 is being rebaselined before more implementation. P1-01 through P1-14 have an initial C++17 implementation, but it is no longer authoritative until reviewed against the revised paper-based `docs/MITC4_FORMULATION.md`. The user added `quad_02.inp` and `quad_02_displacements.csv`; `quad_02` uses `TYPE=S4`, but still includes `Part/Assembly/Instance` and `*Density`, so the next planner must decide whether to normalize it or add a dedicated parser compatibility sprint.
 
 ## Completed Work
 
+### 2026-05-04 - MITC4 formulation reset from local papers
+Author: Codex
+
+Changed files:
+- `docs/Paper/`
+- `docs/MITC4_FORMULATION.md`
+- `docs/ADR.md`
+- `docs/NUMERICAL_CONVENTIONS.md`
+- `docs/README.md`
+- `docs/ABAQUS_INPUT_SUBSET.md`
+- `docs/VERIFICATION_PLAN.md`
+- `references/quad_02.inp`
+- `references/quad_02_displacements.csv`
+- `PLAN.md`
+- `PROGRESS.md`
+
+Summary:
+- Read the local MITC4 paper set under `docs/Paper/` and rewrote `docs/MITC4_FORMULATION.md` as the new Phase 1 formulation contract.
+- Replaced the earlier simplified baseline with degenerated-continuum geometry, convected covariant strain components, FESA/Abaqus S4 tying-point convention, MITC transverse shear interpolation, local/global six-DOF rotation transformation, `2 x 2 x 2` Gauss integration, and thesis-backed drilling stabilization using `drilling_stiffness_scale = 1.0e-3`.
+- Updated ADR-018, numerical conventions, and documentation readiness notes so the old `1.0e-6` averaged-edge baseline is no longer the active rule.
+- Recorded `quad_02` as the new stored S4 reference pair while keeping its `Part/Assembly/Instance` and `*Density` features outside automatic Phase 1 parser acceptance.
+- Updated `PLAN.md` so the next work is a Phase 1 redo/rebaseline, not continuation of the old P1-15/P1-16 path.
+
+Verification:
+- `python scripts/validate_workspace.py` configured CMake, built `fesa_core` and `fesa_tests`, and ran CTest successfully.
+- CTest result: 1 test executable passed.
+
+Follow-up:
+- Draft new Phase 1 redo sprint contracts against the revised MITC4 formulation before modifying solver code.
+- Decide whether `quad_02.inp` should be normalized into the current parser subset or used to justify a dedicated Abaqus/CAE `Part/Assembly/Instance` parser sprint.
+- Decide whether Phase 1 `RF` gets Abaqus `*_reactions.csv` artifacts or remains verified by full-vector equilibrium tests.
+
 ### 2026-05-01 - P1-01 through P1-14 implementation pass
 Author: Codex