fix(math): preflight finite dense operands at dispatch boundary

src/fesa/analysis/eigen_reduction.cpp

@@ -5,6 +5,7 @@
 #include <cmath>
 #include <limits>
 #include <map>
+#include <stdexcept>
 #include <string>
 #include <utility>
 #include <vector>
@@ -226,7 +227,7 @@ Result<EigenReduction> BuildEigenReduction(
     const SparseMatrix& stiffness, const std::vector<Matrix>& mass,
     const std::vector<ShellNodeInitialFrame>& frames,
     const std::vector<std::uint8_t>& mask, const std::vector<double>& drilling,
-    const double length) {
+    const double length) try {
   const std::size_t count = mass.size();
   const Status valid = stiffness.Validate();
   if (!valid.IsOk()) return Result<EigenReduction>::Failure(valid);
@@ -401,6 +402,10 @@ Result<EigenReduction> BuildEigenReduction(
   return Result<EigenReduction>::Success(
       {std::move(reduced.Value()), std::move(lifts), free_count, null_count,
        length, eta_mz, eta_kz, pz_norm});
+} catch (const std::invalid_argument&) {
+  return Result<EigenReduction>::Failure(
+      Failure("invalid-eigen-mass-space", 0U,
+              "Eigen product operands must be finite and shape compatible."));
 }
 
 Vector RestoreScaledMode(const EigenReduction& reduction, const Matrix& vectors,