Test

Add `measure_obs`: persist per-cell centroid/area/equivalent diameter… #1728

Job	Run time
get-environments	9s
hatch-test.py3.14-stable	6m 38s
hatch-test.py3.14-pre (PRE-RELEASE DEPENDENCIES)	2m 46s
hatch-test.py3.11-stable	5m 5s
Tests pass in all hatch environments	3s
	14m 41s

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