Add Windows ARM64 build

[ndabas]

As the title says -- there were only minor changes needed to the matrix:

• Removed the explicit name: so GitHub auto-generates names from the matrix values, because both Windows AMD64 and ARM64 need windows in CIBW_PLATFORM.
• Artifact name is now artifacts-${{ matrix.os }}-${{ matrix.runs-on }}, since matrix.os alone is no longer unique. Qualifying on runs-on alone would have worked too, but artifacts-macos-14 is a misleading name for the iOS wheels.
• pypi_upload still collects everything via pattern: artifacts-* with merge-multiple: true, so the longer names don't affect publishing.