CI: use Visual Studio 2026 generator for Windows ARM64

The windows-11-arm runner image (now windows-11-vs2026-arm64) no
longer ships Visual Studio 2022, so the pinned VS 17 2022 generator
failed with 'could not find any instance of Visual Studio'.

Assisted-by: Kimi Code K3

Author: jdavid

AGENTS.md

@@ -257,8 +257,7 @@ The `cibuildwheel` configuration in `pyproject.toml` pins:
 
 and skips `*musllinux_ppc64le` plus testing on `*-*linux_ppc64le`,
 `*-*linux_riscv64` and `pp*-macosx_arm64`. On Windows it uses the
-`Visual Studio 18 2026` CMake generator for x64/x86 and
-`Visual Studio 17 2022` for ARM64.
+`Visual Studio 18 2026` CMake generator for x64/x86 and ARM64.
 
 ## Security Considerations
 

pyproject.toml

@@ -55,7 +55,7 @@ environment.LIBGIT2 = "C:/libgit2_install_x86"
 [[tool.cibuildwheel.overrides]]
 select="*-win_arm64"
 inherit.environment="append"
-environment.CMAKE_GENERATOR = "Visual Studio 17 2022"
+environment.CMAKE_GENERATOR = "Visual Studio 18 2026"
 environment.CMAKE_GENERATOR_PLATFORM = "ARM64"
 environment.CMAKE_INSTALL_PREFIX = "C:/libgit2_install_arm64"
 environment.LIBGIT2 = "C:/libgit2_install_arm64"