feat: add domain model foundation

include/fesa/core/PropertyDefinition.hpp

@@ -0,0 +1,21 @@
+#pragma once
+
+#include "fesa/core/ModelTypes.hpp"
+
+namespace fesa::core {
+
+class ShellPropertyDefinition {
+public:
+    ShellPropertyDefinition(PropertyId id, MaterialId material_id, double thickness);
+
+    PropertyId id() const noexcept;
+    MaterialId materialId() const noexcept;
+    double thickness() const noexcept;
+
+private:
+    PropertyId id_;
+    MaterialId material_id_;
+    double thickness_;
+};
+
+} // namespace fesa::core