ci: run WinForms and front-end tests on a Windows runner

Pushes to master only ran the Linux job, which can cross-compile but
not execute OpenNest.WinForms.Tests; Windows test runs happened only on
release branches and tags. Add a windows-2022 job to the cross-platform
workflow that runs OpenNest.WinForms.Tests and OpenNest.FrontEnd.Tests
in Release on every master push and pull request, runs both projects
before failing, and uploads their TRX results.

.github/workflows/ci.yml

@@ -32,3 +32,38 @@ jobs:
         run: dotnet test OpenNest.IO.Tests/OpenNest.IO.Tests.csproj
       - name: Run OpenNest.Server.Tests
         run: dotnet test OpenNest.Server.Tests/OpenNest.Server.Tests.csproj
+
+  windows-desktop:
+    # WinForms tests need a Windows desktop runtime; the Linux job can only
+    # cross-compile them. FrontEnd.Tests run here too, alongside the desktop.
+    runs-on: windows-2022
+    timeout-minutes: 30
+    defaults:
+      run:
+        shell: pwsh
+    env:
+      DOTNET_CLI_TELEMETRY_OPTOUT: '1'
+      DOTNET_NOLOGO: '1'
+    steps:
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
+        with:
+          persist-credentials: false
+      - uses: actions/setup-dotnet@67a3573c9a986a3f9c594539f4ab511d57bb3ce9 # v4
+        with:
+          dotnet-version: '8.0.x'
+      - name: Run Windows desktop and front-end tests
+        run: |
+          $failed = @()
+          foreach ($project in @('OpenNest.WinForms.Tests', 'OpenNest.FrontEnd.Tests')) {
+            dotnet test "$project/$project.csproj" -c Release --logger "trx;LogFileName=$project.trx" --results-directory TestResults
+            if ($LASTEXITCODE -ne 0) { $failed += $project }
+          }
+          if ($failed.Count -gt 0) { throw "Failed: $($failed -join ', ')" }
+      - name: Upload test results
+        if: always()
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
+        with:
+          name: windows-desktop-test-results
+          path: TestResults/*.trx
+          if-no-files-found: warn
+          retention-days: 14