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/Models/Workout.swift

@@ -5,7 +5,6 @@ import CoreData
 public class Workout: NSManagedObject, Identifiable {
     @NSManaged public var start: Date
     @NSManaged public var end: Date?
-    @NSManaged private var statusRaw: String
 
     @NSManaged public var split: Split?
     @NSManaged public var logs: NSSet?
@@ -13,13 +12,26 @@ public class Workout: NSManagedObject, Identifiable {
     public var id: NSManagedObjectID { objectID }
 
     var status: WorkoutStatus {
-        get { WorkoutStatus(rawValue: statusRaw) ?? .notStarted }
-        set { statusRaw = newValue.rawValue }
+        get {
+            willAccessValue(forKey: "status")
+            let raw = primitiveValue(forKey: "status") as? String ?? "notStarted"
+            didAccessValue(forKey: "status")
+            return WorkoutStatus(rawValue: raw) ?? .notStarted
+        }
+        set {
+            willChangeValue(forKey: "status")
+            setPrimitiveValue(newValue.rawValue, forKey: "status")
+            didChangeValue(forKey: "status")
+        }
     }
 
     var label: String {
         if status == .completed, let endDate = end {
-            return "\(start.formattedDate())—\(endDate.formattedDate())"
+            if start.isSameDay(as: endDate) {
+                return "\(start.formattedDate())—\(endDate.formattedTime())"
+            } else {
+                return "\(start.formattedDate())—\(endDate.formattedDate())"
+            }
         } else {
             return start.formattedDate()
         }