fix(deps): skip nvidia-cuda-cccl on macOS (no wheels available)

[harkanwalbedi]

Problem

pip install -e ".[dev]" fails on macOS ARM64 / Apple Silicon (reported in #393):

ERROR: Could not find a version that satisfies the requirement nvidia-cuda-cccl>=13.1.115
ERROR: No matching distribution found for nvidia-cuda-cccl>=13.1.115

nvidia-cuda-cccl only publishes manylinux and Windows wheels — no macOS wheels exist — so requiring it unconditionally blocks local developer installs on macOS.

Root Cause

The generated lockfile pinned nvidia-cuda-cccl>=13.1.115 without an environment marker. It is the only NVIDIA package in the lockfile, and no direct dependency requires it unconditionally, so this appears to be a transitive dependency captured during lock resolution on a Linux/CUDA host that lost its platform scoping.

Fix

Add an environment marker matching the package's actual wheel availability:

nvidia-cuda-cccl>=13.1.115 ; sys_platform != 'darwin'

This mirrors the existing treatment of libtpu in the same file (line 92: sys_platform == 'linux') and leaves Linux, Windows, and CI resolution completely untouched.

Verification

Tested on physical hardware (Apple M4 Pro, macOS Sequoia arm64):

• Before: pip install -e ".[dev]" failed with No matching distribution found for nvidia-cuda-cccl>=13.1.115.
• After: Bypasses nvidia-cuda-cccl on Darwin, resolving dependencies without platform failure.

Fixes #393

[gemini-code-assist]

Code Review

This pull request excludes the nvidia-cuda-cccl dependency on macOS by adding an environment marker to the generated requirements file. The reviewer correctly pointed out that manually editing an autogenerated file introduces a maintenance risk as it will be overwritten during the next regeneration, and recommended applying this change to the source requirements file instead.