UCX (Unified Communication X) for CUDA 12

libucx-cu12 is a Python package that provides the Unified Communication X (UCX) C library, specifically compiled with CUDA 12 support, as a distributable wheel. UCX is a low-level, high-performance communication framework for HPC applications, enabling optimized data exchange between CPUs, GPUs, and network interfaces (e.g., InfiniBand, RoCE). This package serves as a backend dependency for Python bindings like `ucx-py` (now `ucxx`), allowing Python applications to leverage UCX capabilities. The current version available on PyPI is `1.19.0`, with upstream UCX having a frequent release cadence including point releases and release candidates.