Remove cstruct objects and remove c-contiguous requirement #586

Job	Run time
mypy	3m 23s
py3.13 \| macos \| integration tests	20m 4s
py3.13 \| macos \| unit tests	7m 28s
py3.13 \| ubuntu \| integration tests	14m 12s
py3.13 \| ubuntu \| unit tests	10m 16s
py3.13 \| windows \| integration tests	24m 16s
py3.13 \| windows \| unit tests	12m 3s
py3.10 \| ubuntu \| integration tests	26m 13s
py3.10 \| ubuntu \| unit tests	10m 54s
py3.11 \| ubuntu \| unit tests	10m 51s
py3.12 \| ubuntu \| unit tests	11m 5s
merge-test-artifacts	2s
	2h 30m 47s

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