Add WatchConnectivity for bidirectional iOS-Watch sync

Implement real-time sync between iOS and Apple Watch apps using
WatchConnectivity framework. This replaces reliance on CloudKit
which doesn't work reliably in simulators.

- Add WatchConnectivityManager to both iOS and Watch targets
- Sync workouts, splits, exercises, and logs between devices
- Update iOS views to trigger sync on data changes
- Add onChange observer to ExerciseView for live progress updates
- Configure App Groups for shared container storage
- Add Watch app views: WorkoutLogsView, WorkoutLogListView, ExerciseProgressView

Workouts Watch App/ContentView.swift

@@ -15,13 +15,7 @@ struct ContentView: View {
     @Environment(\.managedObjectContext) private var viewContext
 
     var body: some View {
-        VStack {
-            Image(systemName: "dumbbell.fill")
-                .imageScale(.large)
-                .foregroundStyle(.tint)
-            Text("Workouts")
-        }
-        .padding()
+        WorkoutLogsView()
     }
 }