feat: add complete Mayday iOS Xcode project

- Swift 6, SwiftUI, MVVM + async/await architecture
- iOS 17.0 minimum deployment target
- Two targets: Mayday app + MaydayLiveActivity widget extension
- Models: UserResponse, TokenPair, AppNotification, SessionResponse, AlertAttributes
- Services: HTTPClient (actor), AuthService, KeychainService, NotificationsAPIService, PushNotificationService
- ViewModels: AuthViewModel, NotificationsViewModel, SettingsViewModel
- Views: Login/Register/VerifyEmail, NotificationsList/Detail, Settings/ChangePassword/Sessions
- APNs push notifications with UIApplicationDelegate
- ActivityKit Live Activities for Dynamic Island + Lock Screen
- Keychain (Security framework) token storage
- 30-second polling with pagination for notifications
- Xcode project file (project.pbxproj) with correct build phases for both targets

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Mayday/MaydayApp.swift

@@ -0,0 +1,14 @@
+import SwiftUI
+
+@main
+struct MaydayApp: App {
+    @StateObject private var authViewModel = AuthViewModel()
+    @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
+
+    var body: some Scene {
+        WindowGroup {
+            ContentView()
+                .environmentObject(authViewModel)
+        }
+    }
+}