CI test management plan: done (#390, #391, #392, #394, #395, #397, #398)
CI test management plan: steps 5 and 6 in review (#395, #397, #398)
CI test management plan: steps 1 and 3 done (#390); 2 and 4 in review (#391, #392)
CI test management plan: step 2 runs 3.13 in full, with VTK, and the quick tier without it
CI test management plan (#369): path filter, one Python version in full, timing tests, flakes, selection, merge queue