Integrate Refactor solver sources and dual MSVC CMake builds

include/fesa/analysis/solid_frequency_procedure.h

@@ -5,14 +5,24 @@
 
 namespace fesa {
 class Domain;
+class EigenSolver;
 /// @brief Executes unloaded reference-state C3D8 generalized frequency
 /// analysis.
 class SolidFrequencyProcedureExecutor final {
  public:
+  /// @brief Preserves default FEAST construction for existing callers.
+  SolidFrequencyProcedureExecutor() = default;
+
+  /// @brief Borrows a solver that must outlive this executor and its calls.
+  explicit SolidFrequencyProcedureExecutor(const EigenSolver& solver) : solver_(&solver) {}
+
   /// @brief Returns lowest requested modes after validating every returned
   /// pair.
   /// @note Domain is immutable and must remain alive during execution.
   Result<SolidFrequencyState> Execute(const Domain& domain) const;
+
+ private:
+  const EigenSolver* solver_{nullptr};
 };
 }  // namespace fesa
 #endif  // FESA_ANALYSIS_SOLID_FREQUENCY_PROCEDURE_H_