Connect HHT field convergence to production acceptance and v2 logs

src/fesa/analysis/hht_dynamic_internal.h

@@ -16,6 +16,7 @@
 #include "fesa/math/sparse_matrix.h"
 #include "elements/nonlinear_mitc4_configuration_internal.h"
 #include "math/dense_blas_internal.h"
+#include "analysis/hht_field_convergence.h"
 
 namespace fesa {
 class LinearSolver;
@@ -95,6 +96,7 @@ struct DynamicAssembly {
   // Canonical scalar drilling-constraint derivative, indexed by global node.
   std::optional<SparseMatrix> hidden_gradient;
   std::optional<TrialConstraintData> trial_constraints;
+  std::array<std::vector<hht_field_convergence::FluxOccurrence>, 2> field_flux;
 };
 
 /// @brief Builds checked shell evaluators in stable source order.
@@ -104,9 +106,17 @@ Result<std::vector<RuntimeShell>> BuildRuntimeShells(const Domain& domain,
 /// @brief Returns the maximum initial active-element edge length.
 Result<double> ReferenceLength(const Domain& domain);
 
+/// @brief Measures free full endpoint residuals and actual u/total-phi changes.
+/// @note Previous is the selected trial in this increment, not a tangent lift.
+Result<std::array<hht_field_convergence::FieldInput, 2>> MeasureEndpointFields(
+    const DofManager& dofs, const DynamicAcceptedFrameState& trial,
+    const DynamicAcceptedFrameState& accepted,
+    const std::optional<Vector>& previous);
+
 /// @brief Assembles dead loads and their uncancelled absolute row scales.
 Result<std::array<Vector, 2>> AssembleLoads(const Domain& domain,
-                                            const DofManager& dofs);
+    const DofManager& dofs,
+    std::array<std::vector<hht_field_convergence::FluxOccurrence>, 2>* field_flux = nullptr);
 
 /// @brief Evaluates current kinetic and internal quantities without commit.
 Result<DynamicAssembly> EvaluateAssembly(