Park the Watch run while iPhone edits an exercise or split

Publish an exclusive-edit lock (editingWorkoutID / editingSplitID) in the
phone→watch application context. While the phone has a workout's exercise
(ExerciseView) or a split (SplitDetailView) open in an editor, the watch pops
out of that run, blocks re-entry, and shows it as "Editing on iPhone" — so the
two devices never drive the same run at once and the watch can't clobber the
phone's edit with a stale optimistic write. The lock clears when the editor
closes; absent keys in the latest-wins context mean "not editing".

Claude-Session: https://claude.ai/code/session_01SCv7zvGFcKy47KSTnTLxRe

Workouts/Views/WorkoutLogs/ExerciseView.swift

@@ -14,6 +14,7 @@ import UIKit
 
 struct ExerciseView: View {
     @Environment(SyncEngine.self) private var sync
+    @Environment(AppServices.self) private var services
     @Environment(\.dismiss) private var dismiss
 
     let workout: Workout
@@ -69,9 +70,12 @@ struct ExerciseView: View {
             progress = log?.currentStateIndex ?? 0
             // Keep the screen lit while logging sets — a mid-workout sleep is annoying.
             UIApplication.shared.isIdleTimerDisabled = true
+            // Take over this run: the watch parks and locks it while we're editing here.
+            services.watchBridge.setEditingWorkout(workout.id)
         }
         .onDisappear {
             UIApplication.shared.isIdleTimerDisabled = false
+            services.watchBridge.setEditingWorkout(nil)
         }
         // Reflect external changes (e.g. a set completed on the watch) live. Each edit
         // rewrites the whole workout file, so the cache always holds the latest — pulling