feat: redesign Dynamic Island with phase-driven UI and animations

tabatago-swift/TabataGo/App/AppState.swift

@@ -2,12 +2,13 @@ import Foundation
 import Observation
 
 /// Global app bootstrap state — initialises all services once at launch.
+@MainActor
 @Observable
 final class AppState {
 
-    var isBootstrapped = false
+    static let shared = AppState()
 
-    @MainActor
+    var isBootstrapped = false
     func bootstrap() async {
         guard !isBootstrapped else { return }
         guard !AppEnvironment.isPreview else { isBootstrapped = true; return }
@@ -15,4 +16,6 @@ final class AppState {
         AnalyticsService.shared.initialize()
         isBootstrapped = true
     }
+
+    private init() {}
 }

tabatago-swift/TabataGo/App/TabataGoApp.swift

@@ -3,20 +3,19 @@ import SwiftData
 
 extension Notification.Name {
     static let skipTrackFromActivity = Notification.Name("skipTrackFromActivity")
+    // togglePauseFromActivity is declared in WorkoutActivityAttributes.swift (shared with widget)
 }
 
 @main
 struct TabataGoApp: App {
 
-    @State private var appState = AppState()
-
     var body: some Scene {
         WindowGroup {
             RootView()
-                .environment(appState)
+                .environment(AppState.shared)
                 .modelContainer(TabataGoSchema.container)
                 .task {
-                    await appState.bootstrap()
+                    await AppState.shared.bootstrap()
                 }
                 .onOpenURL { url in
                     if url.scheme == "tabatago", url.host == "skipTrack" {