Add CI support for building Windows on ARM wheels

[MugundanMCW]

PR Description:

• The adoption of Windows on ARM (WoA) devices is steadily increasing, yet many Python wheels are still not available for this platform.
• GitHub Actions now offer native CI runners for Windows on ARM devices (windows-11-arm), enabling automated builds and testing.
• Currently, official OpenCV Python wheels are not provided for Windows ARM64 and thus users/developers were facing difficulties using popular OpenCV library natively.
• This PR introduces support for building OpenCV wheels on Windows ARM64, improving accessibility for developers and end users on this emerging platform.
• Closes: Can not build the project in W11 on ARM64 #1092, Provide prebuilt Windows ARM64 packages #806

Changes Proposed:

• Added CI workflow for building and testing OpenCV wheels on new Windows on ARM github runners
• Added platform markers to use stable available NumPy for Windows on ARM builds.
• Added Windows on ARM specific condition logic to use NEON as baseline and dispatch unit, since MSVC lacks support for NEON_FP16, NEON_BF16 and NEON_DOTPROD intrinsics.

[MugundanMCW]

Hi @asmorkalov
Just to note here that these changes become obsolete if this PR got merged.

[Avasam]

That PR got merged

[MugundanMCW]

@Avasam thanks, will drop this change from the PR

[Avasam]

Unless I'm missing something big, couldn't .github/workflows/build_wheels_windows_arm.yml be replaced (avoiding tons of duplication that one could forget to update across configs) by updating strategy.matrix and strategy.matrix.include ?

    runs-on: ${{ matrix.os }}
    strategy:
      fail-fast: false
      matrix:
        python-version: ['3.11']
        platform: [x86, x64, arm64]
        with_contrib: [0, 1]
        without_gui: [0, 1]
        build_sdist: [0]
        include:
          - os: 'windows-2025'
          - platform: 'arm64'
            os: 'windows-11-arm'

[Avasam]

Similar here

    runs-on: ${{ matrix.os }}
    defaults:
      run:
        shell: cmd
    strategy:
      fail-fast: false
      matrix:
        python-version: ['3.7', '3.8', '3.9', '3.10', '3.11', '3.12', '3.13']
        platform: [x86, x64, arm64]
        with_contrib: [0, 1]
        without_gui: [0, 1]
        build_sdist: [0]
        include:
          - os: 'windows-2025'
          - platform: 'arm64'
            os: 'windows-11-arm'
        exclude:
          # actions/setup-python does not provide prebuilt arm64 Python before 3.11
          - platform: arm64
            python-version: "3.7"
          - platform: arm64
            python-version: "3.8"
          - platform: arm64
            python-version: "3.9"
          - platform: arm64
            python-version: "3.10"

[MugundanMCW]

Hi @Avasam,

I've addressed all the review comments and made the requested changes. Please let me know if there's anything else needed from my side to help move this PR toward merging.

Thanks!

[MugundanMCW]

Hi @asmorkalov & @Avasam
Could you take a look on the PR? I have adapted the requested changes.
Thanks

[Avasam]

I'm not a maintainer here. Just a contributor like you who's trying to get the best out of OpenCV-Python. Hopefully you get this merged soon because I could also really use it.