Connect MITC4 drilling evidence across analysis procedures

include/fesa/elements/element_capabilities.h

@@ -178,6 +178,8 @@ class ShellReferenceElement : public Element {
   virtual Result<Mitc4Stiffness> Stiffness() const = 0;
   /// @copydoc Mitc4Shell::Mass
   virtual Result<Mitc4Mass> Mass(double density) const = 0;
+  /// @brief Returns the actual immutable reference-kernel drilling formulation.
+  virtual Mitc4DrillingMode DrillingMode() const noexcept = 0;
 };
 
 /// @brief Borrows the same linear MITC4 kernel for stiffness and recovery.
@@ -190,6 +192,7 @@ class Mitc4ReferenceAdapter final : public ShellReferenceElement {
   Result<ElementResultBundle> Recover(const Vector& u) const override;
   Result<Mitc4Stiffness> Stiffness() const override;
   Result<Mitc4Mass> Mass(double density) const override;
+  Mitc4DrillingMode DrillingMode() const noexcept override;
 
  private:
   const Mitc4Shell& kernel_;