# Sprint Contract: IO Parser Extraction

## Objective
Move the Abaqus Phase 1 input parser into the `IO` module while preserving the documented strict parser subset and unsupported-feature diagnostics.

## Required Reading
- /AGENTS.md
- /PROGRESS.md
- /PLAN.md
- /docs/README.md
- /docs/HARNESS_ENGINEERING.md
- /docs/ARCHITECTURE.md
- /docs/ADR.md
- /docs/ABAQUS_INPUT_SUBSET.md
- /docs/VERIFICATION_PLAN.md
- /phases/1-structure-alignment-refactor/step0-architecture-map.md
- /phases/1-structure-alignment-refactor/step2.md

## Scope
- Extract `KeywordLine`, `ParseResult`, `AbaqusInputParser`, and parser-only helpers into `IO`.
- Keep parser output in `Domain`.
- Preserve strict rejection for `S4R`, `Part/Assembly/Instance`, `*Include`, `NLGEOM=YES`, nonzero prescribed displacement, and unsupported keyword parameters.
- Keep normalized reference behavior for `references/quad_02_phase1.inp`.

## Allowed Files
- `include/fesa/fesa.hpp`
- `include/fesa/IO/`
- `src/IO/`
- `include/fesa/Core/`
- `src/Core/`
- `tests/`
- `CMakeLists.txt`
- `phases/1-structure-alignment-refactor/index.json`
- `PLAN.md`
- `PROGRESS.md`

## Explicit Non-Goals
- Do not add new Abaqus keyword support.
- Do not accept original `references/quad_02.inp` as a Phase 1 parser input.
- Do not change `docs/ABAQUS_INPUT_SUBSET.md` unless a purely clarifying note is required.
- Do not move results or reference comparator code in this step.

## Tests To Write First
- Add or update an include/link test for `fesa/IO` parser headers.
- Preserve parser acceptance and rejection tests as characterization tests.
- Ensure original `quad_02.inp` unsupported provenance remains rejected where tested.

## Reference Artifacts
- `references/quad_02.inp`
- `references/quad_02_phase1.inp`

Do not edit these files.

## Acceptance Commands
```bash
python scripts/validate_workspace.py
```

## Evaluator Checklist
- Parser code lives in `IO` and does not own analysis or assembly behavior.
- Parser subset discipline is unchanged.
- Diagnostics still include enough source context for malformed input.
- `Domain` remains the parser output boundary.
- Stored reference compatibility notes remain true.

## Handoff Requirements
- Update this step status in `phases/1-structure-alignment-refactor/index.json`.
- Record moved parser files and any unsupported-feature behavior verified.

## Do Not
- Do not normalize reference files inside parser code.
- Do not silently broaden parser compatibility while refactoring.