fix(ci): make CUDA torch index Linux-only so non-Linux installs work

The cu124 torch/torchvision/torchaudio index was applied to every platform,
but CUDA wheels exist only for Linux/Windows, so `uv sync` failed on macOS
(and any CPU-only box) and the macOS CI leg could never install. Restrict
the cu124 index to sys_platform == 'linux'; macOS/Windows now resolve torch
from PyPI. Also set fail-fast: false so one matrix leg failing no longer
cancels the others.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: InfantLab

.github/workflows/ci-cd.yml

@@ -13,6 +13,7 @@ jobs:
   test:
     runs-on: ${{ matrix.os }}
     strategy:
+      fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest, macos-latest]
         python-version: ["3.12"]

pyproject.toml

@@ -156,10 +156,12 @@ name = "pytorch-cu124"
 url = "https://download.pytorch.org/whl/cu124"
 explicit = true
 
+# CUDA wheels only exist for Linux/Windows; restrict the cu124 index to Linux
+# so macOS and other platforms resolve torch from PyPI (CPU build).
 [tool.uv.sources]
-torch = { index = "pytorch-cu124" }
-torchvision = { index = "pytorch-cu124" }
-torchaudio = { index = "pytorch-cu124" }
+torch = [{ index = "pytorch-cu124", marker = "sys_platform == 'linux'" }]
+torchvision = [{ index = "pytorch-cu124", marker = "sys_platform == 'linux'" }]
+torchaudio = [{ index = "pytorch-cu124", marker = "sys_platform == 'linux'" }]
 
 [tool.ruff]
 line-length = 88  # Keep existing Black line length for consistency