ci: restore Windows matrix now that the Windows build is ready

Author: FinnaXxx

.github/workflows/ci.yml

@@ -11,7 +11,10 @@ concurrency:
 
 jobs:
   test:
-    runs-on: xcode-27
+    strategy:
+      matrix:
+        os: [xcode-27, windows-latest]
+    runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
       - uses: pnpm/action-setup@v4