# Sprint Contract: Results Reference Extraction

## Objective
Move the in-memory result model, Phase 1 results writer, displacement CSV loader, and reference comparator into `Results` while preserving the documented step/frame/field schema.

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

## Scope
- Extract `FieldOutput`, `ResultFrame`, `ResultStep`, `ResultFile`, `InMemoryResultsWriter`, displacement CSV tables, comparison options, and comparison results.
- Preserve mandatory Phase 1 `U` and `RF` field metadata.
- Preserve CSV mapping from Abaqus `Node Label`, `U-U1`, `U-U2`, `U-U3`, `UR-UR1`, `UR-UR2`, `UR-UR3`.
- Keep HDF5 as a future writer adapter; do not add the dependency yet.

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

## Explicit Non-Goals
- Do not add HDF5 output implementation.
- Do not change result labels, field positions, basis, or comparison tolerances.
- Do not add reaction CSV parsing in this step.
- Do not change analysis execution.

## Tests To Write First
- Add or update include/link tests for `fesa/Results` headers.
- Preserve existing result schema, CSV loader, comparison, and `quad_02_phase1` displacement regression tests as characterization tests.

## Reference Artifacts
- `references/quad_02_phase1.inp`
- `references/quad_02_displacements.csv`

Do not edit these files.

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

## Evaluator Checklist
- Result model follows `docs/RESULTS_SCHEMA.md`.
- `U` and `RF` metadata are unchanged.
- CSV comparison still matches by node id, not row order alone.
- `quad_02_phase1` stored displacement regression still passes.
- HDF5 APIs do not leak into solver core.

## Handoff Requirements
- Update this step status in `phases/1-structure-alignment-refactor/index.json`.
- Record moved result/comparator files and any remaining result symbols still left in `fesa.hpp`.

## Do Not
- Do not relax reference tolerances to make relocation pass.
- Do not treat missing Abaqus reaction CSV as solved.