Enable EAS in 2D SOLID elements

[amgebauer]

Enable EAS in 2D solid elements

[Copilot]

Pull request overview

Enables Enhanced Assumed Strain (EAS) support for 2D SOLID2 quad4 elements and adds a regression/patch test exercising the new capability.

Changes:

• Registers quad4 EAS evaluator/formulation (eastype_q4_4) in the solid element factory and explicit template instantiations.
• Extends EAS helper utilities and calc library to handle 2D-specific strain/B-operator and Voigt transforms.
• Adds a new automated test case (including restart) for plane strain quad4 with TECH eas_full.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
tests/list_of_tests.cmake	Adds the new quad4 plane-strain EAS test and restart coverage.
tests/input_files/solid_ele_quad4_stvk_plane_strain_eas.4C.yaml	New patch test input enabling TECH eas_full for 2D quad4 solids.
src/solid_3D_ele/4C_solid_3D_ele_factory.hpp	Extends evaluator type lists to include 2D quad4 EAS integrator.
src/solid_3D_ele/4C_solid_3D_ele_factory.cpp	Adds factory formulation mapping for quad4 + nonlinearTL + full EAS.
src/solid_3D_ele/4C_solid_3D_ele_calc_lib.hpp	Adds 2D strain-gradient and Voigt transformation support; generalizes deformation-gradient reconstruction.
src/solid_3D_ele/4C_solid_3D_ele_calc_eas_helpers.hpp	Adds eastype_q4_4 and adjusts 2D Voigt conversion behavior for enhanced strains.
src/solid_3D_ele/4C_solid_3D_ele_calc.cpp	Adds explicit instantiation for quad4 EAS calculation.
src/solid_3D_ele/4C_solid_3D_ele.cpp	Allows TECH parameter in 2D quad4 input spec (to enable EAS).