fix(ci): pass MSIX file path to msstore publish command

The msstore CLI expects the MSIX file path as the first positional
argument, not a project directory. Using '.' with --inputDirectory
caused "project publisher not found" error.

Author: arcangelo7

.github/workflows/publish-windows.yml

@@ -53,8 +53,9 @@ jobs:
       - name: Upload package to submission
         shell: pwsh
         run: |
-          Write-Host "Uploading package from: msix"
-          msstore publish . --appId $env:APP_ID --inputDirectory msix --noCommit
+          $msixFile = (Get-ChildItem -Path msix -Filter "*.msix" | Select-Object -First 1).FullName
+          Write-Host "Uploading package: $msixFile"
+          msstore publish $msixFile --appId $env:APP_ID --noCommit
 
       - name: Update submission metadata
         shell: pwsh