Prepare system extension support

SFM.System/Application.swift

@@ -0,0 +1,16 @@
+import Library
+import MacLibrary
+import SwiftUI
+
+@main
+struct Application: App {
+    @NSApplicationDelegateAdaptor private var appDelegate: ApplicationDelegate
+
+    init() {
+        Variant.useSystemExtension = true
+    }
+
+    var body: some Scene {
+        MacApplication()
+    }
+}