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/Views/WorkoutLogs/ExerciseView.swift

@@ -125,6 +125,14 @@ struct ExerciseView: View {
         .onAppear {
             progress = Int(workoutLog.currentStateIndex)
         }
+        .onChange(of: workoutLog.currentStateIndex) { _, newValue in
+            // Update local state when CoreData changes (e.g., from Watch sync)
+            if progress != Int(newValue) {
+                withAnimation(.easeInOut(duration: 0.2)) {
+                    progress = Int(newValue)
+                }
+            }
+        }
     }
 
     private func updateLogStatus() {
@@ -162,6 +170,7 @@ struct ExerciseView: View {
 
     private func saveChanges() {
         try? viewContext.save()
+        WatchConnectivityManager.shared.syncAllData()
     }
 }