FESADev/phases/property-model-foundation/step0.md

Step 0: property-base-contract

Read First

Read these files before editing:

• /AGENTS.md
• /docs/PLAN.md
• /docs/PROGRESS.md
• /docs/WORKNOTE.md
• /docs/AGENT_RULES.md
• /docs/ARCHITECTURE.md
• /docs/ADR.md
• /docs/implementation-plans/domain-runtime-storage-implementation-plan.md
• /include/fesa/property/ShellProperty.hpp
• /include/fesa/core/Domain.hpp
• /src/core/Domain.cpp

Task

Create /docs/implementation-plans/property-model-foundation-implementation-plan.md.

The plan must define the runtime property model contract:

• Property is the base class for element properties and sections.
• PropertyKind identifies concrete property families; phase 1 supports only Shell.
• ShellProperty derives from Property.
• Domain owns property objects through RAII.
• Domain validates duplicate property ids and missing material ids.
• Element::propertyId() remains an id reference; elements do not own property objects.

Keep out of scope:

• shell section stiffness;
• material constitutive matrices;
• shear correction;
• element formulation;
• assembly, solver, HDF5 output, and reference comparison.

Tests To Write First

• Documentation-only step. No C++ test is required in this step.

Acceptance Criteria

python -m unittest discover -s scripts -p "test_*.py"

Verification Notes

1. Confirm the plan does not change MITC4 formulation or tolerance policy.
2. Confirm the plan keeps solver state out of Domain.
3. Update phases/property-model-foundation/index.json for this step result.