feat(linear-static-3d-euler-beam): step 20 - mkl-pardiso-solver

include/fesa/solvers/linear/linear_solver.hpp

@@ -0,0 +1,18 @@
+#pragma once
+
+#include "fesa/core/status.hpp"
+
+namespace fesa {
+
+class SparseMatrix;
+class Vector;
+
+// Separates reusable matrix factorization from right-hand-side substitution.
+class LinearSolver {
+public:
+    virtual ~LinearSolver() = default;
+    virtual Status factorize(const SparseMatrix& matrix) = 0;
+    virtual Status solve(const Vector& rhs, Vector& solution) const = 0;
+};
+
+} // namespace fesa