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

TraccarClient/Interface/SettingsView.swift

@@ -0,0 +1,34 @@
+import SwiftUI
+
+struct SettingsView: View {
+    var body: some View {
+        TabView {
+            Form {
+                LabeledContent("Status", value: "Paused")
+                Text("Server and device configuration will be available in a later build.")
+            }
+            .tabItem { Label("Connection", systemImage: "network") }
+
+            Form {
+                Text("Continuous tracking, manual location and SOS are not implemented yet.")
+                Text("This build does not request your location or send positions.")
+            }
+            .tabItem { Label("Tracking", systemImage: "location") }
+
+            Form {
+                Text("Login startup and tracking restoration are not enabled.")
+                Text("Closing Settings keeps the app in the menu bar. Use Quit to exit.")
+            }
+            .tabItem { Label("General", systemImage: "gearshape") }
+
+            Form {
+                LabeledContent("Status", value: "Paused")
+                Text("No location or network activity is started by this application shell.")
+            }
+            .tabItem { Label("Diagnostics", systemImage: "waveform.path.ecg") }
+        }
+        .formStyle(.grouped)
+        .padding()
+        .frame(width: 560, height: 320)
+    }
+}