Awkward Array CUDA backend

[ianna]

• combinations for n > 2

There is an implementation in studies for 2 < n < 5. We want to test if we can extend current cuda kernel with this implementation.

[ianna]

We will move the implementation to a combinations module:

(cuda-cccl) [iosborne@della-gpu awkward]$ git status
On branch ianna/cuda_studies
Changes to be committed:
  (use "git restore --staged <file>..." to unstage)
	new file:   src/awkward/_connect/cuda/combinations/__init__.py
	new file:   src/awkward/_connect/cuda/combinations/combinations_squashed_order_n_3_to_5.py

Where __init__.py:

from .combinations_squashed_order_n_3_to_5 import argchoose

__all__ = [
    "argchoose",
]

Here is the test:

(cuda-cccl) [iosborne@della-gpu awkward]$ python
Python 3.12.11 | packaged by Anaconda, Inc. | (main, Jun  5 2025, 13:09:17) [GCC 11.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from awkward._connect.cuda.combinations import argchoose

[ianna]

@kmohrman - please, check this. Thanks!