Add standalone desktop workflow

internal/disk/storage_windows.go

@@ -0,0 +1,40 @@
+//go:build windows
+
+package disk
+
+import (
+	"path/filepath"
+	"strings"
+
+	"golang.org/x/sys/windows"
+)
+
+func IsMountPoint(path string) bool {
+	clean := filepath.Clean(path)
+	volume := filepath.VolumeName(clean)
+	if volume == "" {
+		return false
+	}
+	root := volume + `\`
+	return strings.EqualFold(clean, root)
+}
+
+func DiskUsage(mountPath string) (total, free int64, err error) {
+	root := filepath.Clean(mountPath)
+	if volume := filepath.VolumeName(root); volume != "" {
+		root = volume + `\`
+	}
+
+	pathPtr, err := windows.UTF16PtrFromString(root)
+	if err != nil {
+		return 0, 0, err
+	}
+
+	var freeBytesAvailable uint64
+	var totalNumberOfBytes uint64
+	var totalNumberOfFreeBytes uint64
+	if err := windows.GetDiskFreeSpaceEx(pathPtr, &freeBytesAvailable, &totalNumberOfBytes, &totalNumberOfFreeBytes); err != nil {
+		return 0, 0, err
+	}
+	return int64(totalNumberOfBytes), int64(freeBytesAvailable), nil
+}