feat: add domain model foundation

include/fesa/core/MaterialDefinition.hpp

@@ -0,0 +1,21 @@
+#pragma once
+
+#include "fesa/core/ModelTypes.hpp"
+
+namespace fesa::core {
+
+class LinearElasticMaterialDefinition {
+public:
+    LinearElasticMaterialDefinition(MaterialId id, double young_modulus, double poisson_ratio);
+
+    MaterialId id() const noexcept;
+    double youngModulus() const noexcept;
+    double poissonRatio() const noexcept;
+
+private:
+    MaterialId id_;
+    double young_modulus_;
+    double poisson_ratio_;
+};
+
+} // namespace fesa::core