refactor: Sandbox for separation of boundaries

sandbox/platform/platform_windows.go

@@ -0,0 +1,16 @@
+//go:build windows
+// +build windows
+
+package platform
+
+import (
+	"errors"
+
+	"github.com/safedep/pmg/sandbox"
+)
+
+// NewSandbox creates a platform-specific sandbox instance for Windows.
+// TODO: Implement AppContainer or Job Objects based sandbox.
+func NewSandbox() (sandbox.Sandbox, error) {
+	return nil, errors.New("sandbox not yet implemented for Windows")
+}