v20260901rc1

Rehearsal for v20260901, published to TestPyPI only.

Packages the dicom3tools snapshot 20260901072548, taken from the
binary archives in
dicom3tools.20260901072548.post4.

Five platform wheels: manylinux_2_17_x86_64, manylinux_2_28_aarch64,
macosx_10_9_x86_64, macosx_11_0_arm64, win_amd64.

Verify with:

pip install --pre -i https://test.pypi.org/simple/ dicom3tools
dciodvfy some.dcm