Fix CI artifact naming conflict

- Change artifact names from 'wheels-{os}-{python}' to 'wheels-{platform_id}-py{python}'
- This prevents 409 conflicts when multiple matrix jobs have the same OS and Python
  but different architectures (e.g., ubuntu-latest with manylinux_x86_64 vs manylinux_aarch64)
- Add overwrite: true to both wheels and sdist artifacts to allow safe re-runs
- The upload_pypi job will still work correctly with pattern: '*' and merge-multiple: true

Author: atksh

.github/workflows/cibuildwheel.yml

@@ -232,8 +232,9 @@ jobs:
           MACOSX_DEPLOYMENT_TARGET: ${{ matrix.macosx_deployment_target }}
       - uses: actions/upload-artifact@v4
         with:
-          name: wheels-${{ matrix.os }}-${{ matrix.python }}
+          name: wheels-${{ matrix.platform_id }}-py${{ matrix.python }}
           path: ./wheelhouse/*.whl
+          overwrite: true
 
   build_sdist:
     name: Build source distribution
@@ -252,6 +253,7 @@ jobs:
         with:
           name: sdist
           path: dist/*.tar.gz
+          overwrite: true
 
   upload_pypi:
     needs: [build_wheels, build_sdist]