fix: configure CMake paths in pyproject.toml for proper Homebrew detection

- Add CMAKE_PREFIX_PATH and OpenMP_ROOT environment variable mapping in both backends
- Remove CMAKE_ARGS from GitHub Actions workflow (cleaner separation)
- Ensure scikit-build-core correctly uses environment variables for CMake configuration
- This should fix the hardcoded /opt/homebrew paths on Intel Macs

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

.github/workflows/build-reusable.yml

@@ -150,8 +150,6 @@ jobs:
             export CC=clang
             export CXX=clang++
             export MACOSX_DEPLOYMENT_TARGET=11.0
-            # Pass CMAKE_PREFIX_PATH to help CMake find Homebrew packages
-            export CMAKE_ARGS="-DCMAKE_PREFIX_PATH=${CMAKE_PREFIX_PATH} -DOpenMP_ROOT=${OpenMP_ROOT}"
             uv build --wheel --python python
           else
             uv build --wheel --python python
@@ -166,8 +164,6 @@ jobs:
             export CXX=clang++
             # DiskANN requires macOS 13.3+ for sgesdd_ LAPACK function
             export MACOSX_DEPLOYMENT_TARGET=13.3
-            # Pass CMAKE_PREFIX_PATH to help CMake find Homebrew packages
-            export CMAKE_ARGS="-DCMAKE_PREFIX_PATH=${CMAKE_PREFIX_PATH} -DOpenMP_ROOT=${OpenMP_ROOT}"
             uv build --wheel --python python
           else
             uv build --wheel --python python