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 Watch App/Views/ActiveWorkoutGateView.swift

@@ -23,6 +23,11 @@ struct ActiveWorkoutGateView: View {
     @Query(sort: \Workout.start, order: .reverse) private var workouts: [Workout]
     @Query private var splits: [Split]
 
+    /// Navigated workouts (depth 1). Held here — rather than relying on implicit
+    /// `NavigationLink` destinations — so we can pop back to the gate the moment the phone
+    /// takes over editing the run we're inside.
+    @State private var path: [ActiveWorkoutRoute] = []
+
     private var activeWorkouts: [Workout] {
         workouts.filter { $0.status == .inProgress || $0.status == .notStarted }
     }
@@ -32,24 +37,36 @@ struct ActiveWorkoutGateView: View {
         return splits.first { $0.id == id }
     }
 
+    /// True while the phone has this workout's exercise — or the split it came from — open
+    /// in an editor. The watch parks such a run and blocks re-entry so the phone owns the
+    /// edit and the watch can't forward a stale optimistic write over it.
+    private func isLockedForEditing(_ workout: Workout) -> Bool {
+        if let id = bridge.editingWorkoutID, id == workout.id { return true }
+        if let splitID = bridge.editingSplitID, splitID == workout.splitID { return true }
+        return false
+    }
+
     var body: some View {
-        NavigationStack {
+        NavigationStack(path: $path) {
             Group {
                 if activeWorkouts.isEmpty {
                     emptyState
                 } else {
                     List {
                         ForEach(activeWorkouts) { workout in
-                            NavigationLink {
-                                WorkoutLogListView(workout: workout)
-                            } label: {
-                                ActiveWorkoutRow(workout: workout, split: split(for: workout))
-                            }
+                            row(for: workout)
                         }
                     }
                     .navigationTitle("In Progress")
                 }
             }
+            .navigationDestination(for: ActiveWorkoutRoute.self) { route in
+                // Resolve from the full set (not just active) so a run that finishes while
+                // you're inside it still renders rather than blanking.
+                if let workout = workouts.first(where: { $0.id == route.workoutID }) {
+                    WorkoutLogListView(workout: workout)
+                }
+            }
         }
         .task {
             // Nothing to run yet — pull fresh state in case the phone just started one.
@@ -60,6 +77,28 @@ struct ActiveWorkoutGateView: View {
             // was keeping the launched app alive.
             if noActiveWorkouts { sessionManager.end() }
         }
+        // The phone just entered (or left) an editor — if we're inside the now-locked run,
+        // pop back to the gate so re-entry rebuilds a fresh working copy.
+        .onChange(of: bridge.editingWorkoutID) { _, _ in popIfNavigatedRunLocked() }
+        .onChange(of: bridge.editingSplitID) { _, _ in popIfNavigatedRunLocked() }
+    }
+
+    @ViewBuilder
+    private func row(for workout: Workout) -> some View {
+        if isLockedForEditing(workout) {
+            ActiveWorkoutRow(workout: workout, split: split(for: workout), editingOnPhone: true)
+        } else {
+            NavigationLink(value: ActiveWorkoutRoute(workoutID: workout.id)) {
+                ActiveWorkoutRow(workout: workout, split: split(for: workout))
+            }
+        }
+    }
+
+    /// If the run we're currently navigated into has become locked, pop to the gate.
+    private func popIfNavigatedRunLocked() {
+        guard let route = path.last,
+              let workout = workouts.first(where: { $0.id == route.workoutID }) else { return }
+        if isLockedForEditing(workout) { path.removeAll() }
     }
 
     private var emptyState: some View {
@@ -82,13 +121,15 @@ struct ActiveWorkoutGateView: View {
 private struct ActiveWorkoutRow: View {
     let workout: Workout
     let split: Split?
+    /// When true, the phone is editing this run — render it dimmed and non-tappable.
+    var editingOnPhone: Bool = false
 
     private var logs: [WorkoutLog] { workout.logsArray }
     private var doneCount: Int { logs.filter { $0.status == .completed }.count }
 
     var body: some View {
         HStack(spacing: 10) {
-            Image(systemName: split?.systemImage ?? "figure.strengthtraining.traditional")
+            Image(systemName: editingOnPhone ? "pencil" : (split?.systemImage ?? "figure.strengthtraining.traditional"))
                 .font(.title3)
                 .foregroundStyle(split.map { Color.color(from: $0.color) } ?? .workTint)
                 .frame(width: 26)
@@ -103,11 +144,22 @@ private struct ActiveWorkoutRow: View {
                     .foregroundStyle(.secondary)
             }
         }
+        .opacity(editingOnPhone ? 0.5 : 1)
     }
 
     private var subtitle: String {
+        if editingOnPhone { return "Editing on iPhone…" }
         guard !logs.isEmpty else { return workout.start.formattedDate() }
         if doneCount == 0 { return "Not started · \(logs.count) exercises" }
         return "\(doneCount) of \(logs.count) done"
     }
 }
+
+// MARK: - Navigation
+
+/// Stable, hashable handle for a navigated run. Keyed by id (not the `Workout` object) so
+/// the path survives cache rebuilds, and a distinct type so it never collides with the
+/// log-id destination inside `WorkoutLogListView`.
+private struct ActiveWorkoutRoute: Hashable {
+    let workoutID: String
+}