Fix merge step: install wheel into system Python

The merge_cuda_core_wheels.py script runs with the system Python
(3.12 from setup-python1), not the venv. Use --system so the wheel
package is available to the system Python.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: kkraus14

.gitattributes

@@ -14,7 +14,8 @@ cuda_core/cuda/core/_cpp/*.hpp -binary text diff
 *.svg binary
 # SCM syntax highlighting & preventing 3-way merges
 pixi.lock merge=binary linguist-language=YAML linguist-generated=true
-uv.lock merge=binary linguist-language=TOML linguist-generated=true# "export-subst" specifies that this file will get filled in with the current
+uv.lock merge=binary linguist-language=TOML linguist-generated=true
+# "export-subst" specifies that this file will get filled in with the current
 # commit and tag information when running `git archive`.  This allows
 # `setuptools-scm` to correctly determine the version when building from a git
 # archive.  See #1609.

.github/workflows/build-wheel.yml

@@ -470,7 +470,7 @@ jobs:
 
       - name: Merge cuda.core wheels
         run: |
-          uv pip install wheel
+          uv pip install --system wheel
           python ci/tools/merge_cuda_core_wheels.py \
             "${{ env.CUDA_CORE_ARTIFACTS_DIR }}"/cu"${BUILD_CUDA_MAJOR}"/cuda_core*.whl \
             "${{ env.CUDA_CORE_ARTIFACTS_DIR }}"/cu"${BUILD_PREV_CUDA_MAJOR}"/cuda_core*.whl \