Merge remote-tracking branch 'upstream/master' into merge_refactor

pySDC/helpers/spectral_helper.py

pySDC/implementations/problem_classes/RayleighBenard.py

pySDC/implementations/problem_classes/generic_spectral.py

pySDC/playgrounds/PinT_Workshop_2025/0_pySDC.ipynb

.../playgrounds/PinT_Workshop_2025/1_Add_problem_class.ipynb

...ds/PinT_Workshop_2025/2_Coupling_pySDC_to_libraries.ipynb

pySDC/playgrounds/PinT_Workshop_2025/README.rst

...C/playgrounds/PinT_Workshop_2025/environment-tutorial.yml

pySDC/playgrounds/PinT_Workshop_2025/figs/3D_RBC_3.png

..._2025/figs/ADVECTION_steps_vs_iteration_hf_7x7_INTERP.png

pySDC/playgrounds/PinT_Workshop_2025/figs/GS3D_000040.png

...pression_order_time_advection_d=1.00e-06_n=4_MPI=True.png

...rkshop_2025/figs/parallelSDC_preconditioner_vanderpol.png

...playgrounds/PinT_Workshop_2025/figs/scaling_GS3D_time.png

...inT_Workshop_2025/figs/timings_SDC_variants_GrayScott.png

..._Workshop_2025/figs/wp-run_RBC-RK_comp-t-e_global_rel.png

pySDC/projects/Monodomain/etc/environment-monodomain.yml

pySDC/tests/test_helpers/test_spectral_helper.py