Fix WinGet installation in GitHub Actions for ARM64 Windows CI

Added WinGet installation step using Add-AppxPackage to resolve dependency
installation issues on ARM64 Windows runners. WinGet provides better ARM64
package support than Scoop for this platform.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: WebKit ARM64 Builder

.github/workflows/build.yml

@@ -256,6 +256,9 @@ jobs:
     steps:
       - name: Install dependencies via WinGet
         run: |
+          # Install WinGet first (not available by default on GitHub Actions)
+          Add-AppxPackage -RegisterByFamilyName -MainPackage Microsoft.DesktopAppInstaller_8wekyb3d8bbwe
+          
           # Install all required tools via WinGet (has better ARM64 support)
           winget install --id=Kitware.CMake -e --silent --accept-source-agreements --accept-package-agreements
           winget install --id=Ninja-build.Ninja -e --silent --accept-source-agreements --accept-package-agreements