perf(allocations): reduced overall allocations by 95%, increaseed jacobian applicatin by 2x

This commit uses global pre allocated work space to dramatically reduce memory usage and allocation time

libmeanfield/interface/operators/stellar_equilibrium_problem.cppm

@@ -298,6 +298,13 @@ export namespace mean_field::equilibrium {
             m_preparedOperator.Mult(direction, action);
         }
 
+        void BuildVolumeDisplacementDirection(
+            const mfem::Vector &stateDirection,
+            mfem::Vector &volumeDisplacementDirection
+        ) const {
+            m_preparedOperator.BuildVolumeDisplacementDirection(stateDirection, volumeDisplacementDirection);
+        }
+
     private:
         [[nodiscard]] static CompiledSurfaceConstraintType CompileSurfaceConstraint(const ModelType &stellarModel) {
             return surface::compilePressureSurfaceConstraint<