feat: add eigen2 frequency pipeline and fail-closed validation

Implement MITC4 mass, constrained whitening, MKL FEAST, modal HDF5, and deterministic Value comparison. MSVC Debug builds; 394 of 395 tests pass. Original-model all-c residual and the documented S3 static contract conflict remain unresolved; this is an implementation checkpoint, not feature acceptance.

src/fesa/app/fesa_application.cpp

@@ -5,6 +5,7 @@
 #include <string>
 #include <vector>
 
+#include "fesa/analysis/linear_frequency_procedure.h"
 #include "fesa/analysis/linear_static_procedure.h"
 #include "fesa/analysis/newton_iteration_log.h"
 #include "fesa/analysis/nonlinear_static_procedure.h"
@@ -12,6 +13,7 @@
 #include "fesa/app/output_paths.h"
 #include "fesa/assembly/parallel_for.h"
 #include "fesa/core/diagnostic.h"
+#include "fesa/io/hdf5/eigen_hdf5_results_writer.h"
 #include "fesa/io/hdf5/hdf5_results_writer.h"
 #include "fesa/io/hdf5/nonlinear_hdf5_results_writer.h"
 #include "fesa/solvers/linear/mkl_pardiso_solver.h"
@@ -63,8 +65,8 @@ int ExitCodeFor(const Status& status) {
 }  // namespace
 
 int FesaApplication::Run(const std::vector<std::string>& arguments) {
-  const auto paths = DeriveSingleInputOutputPaths(
-      arguments, std::filesystem::current_path());
+  const auto paths =
+      DeriveSingleInputOutputPaths(arguments, std::filesystem::current_path());
   if (!paths.HasValue()) {
     WriteDiagnostics(paths.GetStatus().Diagnostics());
     return kUsageExitCode;
@@ -81,6 +83,7 @@ int FesaApplication::Run(const std::vector<std::string>& arguments) {
   MklPardisoTangentSolver tangent_solver;
   Hdf5ResultsWriter linear_writer;
   NonlinearHdf5ResultsWriter nonlinear_writer;
+  EigenHdf5ResultsWriter eigen_writer;
   NewtonIterationLogWriter log;
 
   Status status = log.Open(paths.Value().log_path);
@@ -96,9 +99,11 @@ int FesaApplication::Run(const std::vector<std::string>& arguments) {
   } else {
     LinearStaticProcedureExecutor linear_executor(parallel_for, linear_solver);
     NonlinearStaticProcedureExecutor nonlinear_executor(parallel_for,
-                                                         tangent_solver);
-    Result<PreparedAnalysisOutcome> outcome = ExecutePreparedAnalysis(
-        prepared.Value().domain, linear_executor, nonlinear_executor, log);
+                                                        tangent_solver);
+    const LinearFrequencyProcedureExecutor frequency_executor;
+    Result<PreparedAnalysisOutcome> outcome =
+        ExecutePreparedAnalysis(prepared.Value().domain, linear_executor,
+                                nonlinear_executor, frequency_executor, log);
     if (!outcome.HasValue()) {
       status = outcome.GetStatus();
     } else {
@@ -109,7 +114,8 @@ int FesaApplication::Run(const std::vector<std::string>& arguments) {
       }
       status = FinalizePreparedAnalysisResult(
           paths.Value(), prepared.Value().domain, outcome.Value(),
-          prepared.Value().diagnostics, linear_writer, nonlinear_writer);
+          prepared.Value().diagnostics, linear_writer, nonlinear_writer,
+          eigen_writer);
       if (status.IsOk()) {
         return kSuccessExitCode;
       }