feat: add native macOS menu-bar application shell (#1)

TraccarClient/Interface/TrackingMenu.swift

@@ -0,0 +1,45 @@
+import AppKit
+import SwiftUI
+
+struct TrackingMenu: View {
+    @Environment(\.openSettings) private var openSettings
+
+    var body: some View {
+        Text("Paused")
+        Text("Tracking is not available in this build.")
+
+        Divider()
+
+        Button("Start tracking") {}
+            .disabled(true)
+        Button("Send location now") {}
+            .disabled(true)
+        Button("Send SOS") {}
+            .disabled(true)
+
+        Divider()
+
+        Button("Settings…") {
+            NSApplication.shared.activate(ignoringOtherApps: true)
+            openSettings()
+        }
+        .keyboardShortcut(",")
+
+        Button("About Traccar Client for macOS") {
+            NSApplication.shared.activate(ignoringOtherApps: true)
+            NSApplication.shared.orderFrontStandardAboutPanel(options: [
+                .applicationName: "Traccar Client for macOS",
+                .credits: NSAttributedString(
+                    string: "An independent, unofficial Traccar client.\nLicensed under Apache License 2.0."
+                ),
+            ])
+        }
+
+        Divider()
+
+        Button("Quit Traccar Client macOS") {
+            NSApplication.shared.terminate(nil)
+        }
+        .keyboardShortcut("q")
+    }
+}