Add quick test and fix Windows clipboard check

Run `go test -v ./...` in the release workflow before GoReleaser.
In the Windows test job replace Get-Clipboard with
System.Windows.Forms::GetFileDropList(), check for "$PWD\ctx.txt" and
improve success/error output.

.github/workflows/release.yaml

@@ -22,6 +22,10 @@ jobs:
         with:
           go-version: stable
 
+      - name: Quick Sanity Check
+        shell: bash
+        run: go test -v ./...
+
       - name: Run GoReleaser
         uses: goreleaser/goreleaser-action@v6
         with: