fix(equation-and-linear-solve): address review findings

include/fesa/constraints/essential_bc.hpp

@@ -1,6 +1,5 @@
 #pragma once
 
-#include <cstddef>
 #include <optional>
 #include <span>
 #include <vector>
@@ -8,15 +7,12 @@
 #include <fesa/assembly/equation_system.hpp>
 #include <fesa/core/diagnostic.hpp>
 #include <fesa/fem/dof_manager.hpp>
-#include <fesa/model/step_definition.hpp>
 
 namespace fesa {
 
 struct ReducedSystem final {
     SymmetricCsr stiffness;
     std::vector<double> force;
-    std::vector<std::size_t> free_to_full;
-    std::vector<double> prescribed_full;
 };
 
 struct ConstraintResult final {
@@ -26,8 +22,7 @@ struct ConstraintResult final {
 
 [[nodiscard]] ConstraintResult eliminate_essential_bcs(
     const EquationSystem& original,
-    const DofManager& dofs,
-    std::span<const PrescribedDof> prescribed);
+    const DofManager& dofs);
 
 [[nodiscard]] std::vector<double> recover_reaction(
     const EquationSystem& original,