Implement upstream changes from scikit-image 0.23 (part 1 of 2)

[grlee77]

This MR updates cuCIM for consistency with version scikit-image 0.23.2rc1. There were a relatively large number of changes in the morphology module, so I am going to submit those in a subsequent MR. I will also bump the scikit-image version pinning as part of that second MR.

The commits in this MR can be reviewed individually. Much of the new code is private functions in cucim.skimage._shared that are copied from upstream and don't need to be reviewed in detail.

The highlights are:

• cucim.skimage.measure.regionprops (and regionprops_table) support one new region property: intensity_std
• cucim.skimage.segmentation.expand_labels now supports a spacing keyword argument to take a pixel's physical dimensions into account.
• additional modules use __init__.pyi instead of just __init__.py
• various fixes to documentation strings (consistent shape notation, etc.)
• adopted the private _shared/compat.py for future NumPy 2.0/SciPy compatibility
• adopted private test utility assert_stacklevel
• updated the private utility functions for handling deprecations to match those upstream
  • update existing decorators to the new ones
  • new rename of output->out for cucim.skimage.filters.gaussian