# Sprint Contract: Core Domain DOF Extraction

## Objective
Move core types, diagnostics, domain data, validation, `AnalysisModel`, `DofManager`, and Phase 1 boundary/load/property model ownership out of the monolithic header into the documented `Core`, `Util`, `Boundary`, `Load`, and `Property` module boundaries.

## Required Reading
- /AGENTS.md
- /PROGRESS.md
- /PLAN.md
- /docs/README.md
- /docs/HARNESS_ENGINEERING.md
- /docs/ARCHITECTURE.md
- /docs/ADR.md
- /docs/NUMERICAL_CONVENTIONS.md
- /phases/1-structure-alignment-refactor/step0-architecture-map.md
- /phases/1-structure-alignment-refactor/step1.md

## Scope
- Extract numeric aliases, diagnostics, DOF enum/mapping, domain entities, domain validation helpers, `AnalysisModel`, and `DofManager`.
- Extract Phase 1 `BoundaryCondition`, `NodalLoad`, and `ShellSection` ownership into `Boundary`, `Load`, and `Property` module headers or implementation files while keeping `Domain` as the aggregate input model.
- Keep `Node` and `Element` free of equation ids.
- Keep `Domain` as input-model ownership and treat it as immutable after parsing.
- Preserve existing symbol names and the `fesa` namespace unless a compiler-visible conflict requires a narrow adjustment.

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

## Explicit Non-Goals
- Do not move parser, MITC4 element, assembly, analysis, solver, material-law, or result writer code in this step except for include dependency repair.
- Do not change DOF order or Abaqus DOF mapping.
- Do not change reaction recovery formulas.
- Do not add runtime polymorphic interfaces that are not needed for this extraction.

## Tests To Write First
- Add or update focused tests proving module includes expose `DofManager`, `Domain`, diagnostics, DOF mapping, Phase 1 boundary/load/property model types, and the umbrella header.
- Preserve existing DofManager and domain validation behavioral tests as characterization tests.

## Reference Artifacts
- None.

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

## Evaluator Checklist
- Core ownership matches `docs/ARCHITECTURE.md`.
- Boundary, Load, and Property Phase 1 model types are no longer hidden only in `fesa.hpp`.
- `DofManager` still owns constrained/free mapping, equation numbering, sparse connectivity inputs, and full-vector reconstruction.
- Numeric aliases remain `double` and signed int64.
- `Node` and `Element` do not store global equation ids.
- Existing parser, analysis, and reference tests still pass.

## Handoff Requirements
- Update this step status in `phases/1-structure-alignment-refactor/index.json`.
- Record moved files and any remaining Core symbols still left in `fesa.hpp`.
- Update `PLAN.md` if the extraction reveals a dependency cycle that requires a later contract change.

## Do Not
- Do not weaken tests to accommodate include-order problems.
- Do not let `Core` depend on `IO`, `Element`, `Assembly`, `Analysis`, or `Results`.
- Do not create circular dependencies between `Core`, `Boundary`, `Load`, and `Property`.