pixtreme 1.9.0

pixtreme 1.9.0 moves its GPU dependencies from the CUDA 12 builds to the CUDA 13 builds, including CuPy
(cupy-cuda13x). It requires NVIDIA driver R580 or newer and an NVIDIA GPU with compute capability 7.5 or higher;
use pixtreme 1.8.0 for CUDA 12 environments. Public operation names, arguments, accepted names, and return shapes
remain compatible.
The published performance report (docs/performance.md) and README performance table still show the earlier
CUDA 12.9 baseline measured at commit 260fe6e; CUDA 13 measurements have not been taken for this release.

Changed

• pixtreme now requires CUDA 13 builds of its GPU dependencies, NVIDIA driver R580 or newer, and an NVIDIA GPU
  with compute capability 7.5 or higher. Applications pinned to CUDA 12 dependency builds must migrate to CUDA 13;
  drivers older than R580 and GPUs with compute capability 7.0 or lower are no longer supported.