Fix windows-2025 example builds by passing MSVC aligned-storage define through nvcc

[Copilot]

The Test Examples Build workflow was failing on windows-2025 (CUDA 12.6.3) during @rules_cuda_examples//basic:all because MSVC STL static assertions were triggered in nvcc host compilation.
This change updates the Windows CI build flags so nvcc forwards the required MSVC define.

• CI workflow change (.github/workflows/build-tests.yaml)

  • In the Windows MSVC compatibility step, add:
    • --@rules_cuda//cuda:copts=-Xcompiler=/D_ENABLE_EXTENDED_ALIGNED_STORAGE
  • Keep existing _ALLOW_COMPILER_AND_STL_VERSION_MISMATCH behavior intact.

• Effect on failing job

  • Aligns NVCC+MSVC invocation on windows-2025 with VS 2025 STL requirements.
  • Targets only Windows matrix jobs; no Linux/LLVM path changes.

- name: Bazel build config to allow unsupported compilers (MSVC)
  if: ${{ startsWith(matrix.cases.os, 'windows') }}
  run: |
    echo "build --@rules_cuda//cuda:copts=-D=_ALLOW_COMPILER_AND_STL_VERSION_MISMATCH" >> $HOME/.bazelrc
    echo "build --@rules_cuda//cuda:copts=-Xcompiler=/D_ENABLE_EXTENDED_ALIGNED_STORAGE" >> $HOME/.bazelrc