docs: redefine phase 1 rebaseline steps

phases/1-linear-static-mitc4-rebaseline/step11.md

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+# Sprint Contract: MITC4 Patch Benchmark Tests
+
+## Objective
+Add element-level and small-mesh MITC4 patch and benchmark tests before integrating stored Abaqus references.
+
+## Required Reading
+- /AGENTS.md
+- /docs/MITC4_FORMULATION.md
+- /docs/VERIFICATION_PLAN.md
+- /docs/NUMERICAL_CONVENTIONS.md
+
+## Scope
+- Add constant membrane, pure bending, pure shear, pure twist, rigid-body, and drilling sensitivity tests.
+- Add a thin cantilever or plate strip test to expose shear locking.
+- Add benchmark scaffolding for Scordelis-Lo after flat tests pass.
+
+## Allowed Files
+- `tests/`
+- `include/`
+- `src/` only for minimal fixes required by tests
+- `docs/VERIFICATION_PLAN.md` only for clarifying benchmark notes
+- `PLAN.md`
+- `PROGRESS.md`
+
+## Explicit Non-Goals
+- Do not require Abaqus execution.
+- Do not add pressure loads for Scordelis-Lo in Phase 1.
+- Do not hide failing element behavior by loosening tolerances without rationale.
+
+## Tests To Write First
+- The patch and benchmark tests are the sprint output; write them before any fixes.
+- Include at least one negative or sensitivity test for drilling scale effects.
+
+## Reference Artifacts
+- Local analytic or hand-check benchmark data only.
+- Stored Abaqus CSV regression is reserved for step 14.
+
+## Acceptance Commands
+```bash
+python scripts/validate_workspace.py
+```
+
+## Evaluator Checklist
+- Tests cover locking-sensitive behavior, not only shape functions.
+- Tolerances are scale-aware and documented.
+- Any implementation fixes remain minimal and within MITC4 scope.
+
+## Handoff Requirements
+- Record benchmark coverage and remaining gaps in `PROGRESS.md` and `PLAN.md`.
+
+## Do Not
+- Do not implement new load types to force a benchmark into Phase 1.