Integrate Refactor solver sources and dual MSVC CMake builds

include/fesa/constraints/essential_constraint_policy.h

@@ -24,6 +24,16 @@ class EssentialConstraintPolicy {
   Result<PartitionedStiffness> Partition(const SparseMatrix& full_stiffness,
                                          const DofManager& dof_manager) const;
 
+  /// @brief Forms Ff-Kfc*dc in stable free/constrained order.
+  /// @return A finite RHS candidate or the established load diagnostic.
+  /// @note Preserves independent CSR products and ordered row reductions;
+  /// no factorization or solver operation is performed. Inputs are borrowed
+  /// only for this call and remain unchanged on failure.
+  Result<Vector> EffectiveFreeRhs(const Vector& full_load,
+                                   const SparseMatrix& kfc,
+                                   const Vector& prescribed_values,
+                                   const DofManager& dofs) const;
+
   /// @brief Gathers a full vector in stable free-equation order.
   Vector GatherFree(const Vector& full_values,
                     const DofManager& dof_manager) const;

include/fesa/constraints/prescribed_displacement.h

@@ -5,7 +5,7 @@
 
 #include "fesa/constraints/boundary_condition.h"
 #include "fesa/core/diagnostic.h"
-#include "fesa/elements/element.h"
+#include "fesa/elements/element_dof_layout.h"
 #include "fesa/model/source_target_resolver.h"
 
 namespace fesa {