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/Connectivity/WatchConnectivityBridge.swift

@@ -16,6 +16,13 @@ final class WatchConnectivityBridge: NSObject {
     /// Last time state was received from the phone (for a sync indicator).
     private(set) var lastSyncDate: Date?
 
+    /// Exclusive-edit lock pushed by the phone. While set, the watch parks the matching
+    /// run (popping out of its progress view) and blocks re-entry, so the phone owns the
+    /// edit and the watch can't clobber it with a stale optimistic write. `editingWorkoutID`
+    /// matches a run by its workout id; `editingSplitID` matches any run by its `splitID`.
+    private(set) var editingWorkoutID: String?
+    private(set) var editingSplitID: String?
+
     private var context: ModelContext { container.mainContext }
 
     init(container: ModelContainer) {
@@ -30,9 +37,11 @@ final class WatchConnectivityBridge: NSObject {
         session.activate()
         self.session = session
         // Apply whatever the phone last pushed, then ask for a fresh push.
-        applyState(WCPayload.decodeSplits(session.receivedApplicationContext),
-                   workouts: WCPayload.decodeWorkouts(session.receivedApplicationContext))
-        applySettings(session.receivedApplicationContext)
+        let ctx = session.receivedApplicationContext
+        applyState(WCPayload.decodeSplits(ctx), workouts: WCPayload.decodeWorkouts(ctx))
+        applySettings(ctx)
+        editingWorkoutID = WCPayload.decodeEditingWorkoutID(ctx)
+        editingSplitID = WCPayload.decodeEditingSplitID(ctx)
         requestSync()
     }
 
@@ -105,10 +114,15 @@ extension WatchConnectivityBridge: WCSessionDelegate {
         let workouts = WCPayload.decodeWorkouts(applicationContext)
         let rest = WCPayload.decodeRestSeconds(applicationContext)
         let done = WCPayload.decodeDoneCountdownSeconds(applicationContext)
+        let editingWorkoutID = WCPayload.decodeEditingWorkoutID(applicationContext)
+        let editingSplitID = WCPayload.decodeEditingSplitID(applicationContext)
         Task { @MainActor in
             self.applyState(splits, workouts: workouts)
             if let rest { UserDefaults.standard.set(rest, forKey: WCPayload.restSecondsKey) }
             if let done { UserDefaults.standard.set(done, forKey: WCPayload.doneCountdownSecondsKey) }
+            // Absent keys mean "not editing" — set unconditionally so the lock clears.
+            self.editingWorkoutID = editingWorkoutID
+            self.editingSplitID = editingSplitID
         }
     }
 }