fix(ios): keep NWC Live Activity on playing track during in-app pick

ios/NWCWidget/NWCLiveActivityShared.swift

@@ -10,6 +10,7 @@ enum NWCLiveActivityShared {
     private static let keyIsMuted = "nwc.isMuted"
     private static let keyRevision = "nwc.contentRevision"
     private static let keyActivityId = "nwc.activityId"
+    private static let keyPreferredTrackIndex = "nwc.preferredTrackIndex"
 
     private static var defaults: UserDefaults? {
         UserDefaults(suiteName: appGroupID)
@@ -36,6 +37,19 @@ enum NWCLiveActivityShared {
         d?.set(Int(revision), forKey: keyRevision)
     }
 
+    /// Track the user prefers next start to play. Distinct from the display state
+    /// (`keyTrackIndex`) so picking in settings during an active session doesn't
+    /// race the refresh timer into showing a track the audio isn't actually playing.
+    static func readPreferredTrackIndex() -> Int? {
+        guard let d = defaults, d.object(forKey: keyPreferredTrackIndex) != nil
+        else { return nil }
+        return d.integer(forKey: keyPreferredTrackIndex)
+    }
+
+    static func writePreferredTrackIndex(_ index: Int) {
+        defaults?.set(index, forKey: keyPreferredTrackIndex)
+    }
+
     static func setPreferredActivityId(_ id: String?) {
         let d = defaults
         if let id {
@@ -125,6 +139,7 @@ enum NWCLiveActivityShared {
     static func applyNextTrack() async {
         var (index, muted, _) = readDisplay()
         index = (index + 1) % max(tracks.count, 1)
+        writePreferredTrackIndex(index)
         await pushLiveActivity(trackIndex: index, isMuted: muted)
     }
 
@@ -133,6 +148,7 @@ enum NWCLiveActivityShared {
         var (index, muted, _) = readDisplay()
         let count = max(tracks.count, 1)
         index = (index - 1 + count) % count
+        writePreferredTrackIndex(index)
         await pushLiveActivity(trackIndex: index, isMuted: muted)
     }
 

ios/zeus/NWCAudioKeepAlive.m

@@ -118,10 +118,11 @@ RCT_EXPORT_MODULE();
         _disconnectCount   = 0;
         _trackNames        = [NWCAmbientTracks trackNames];
 
-        // Restore last-selected track from the app group (written by
-        // switchToTrackAtIndex: via NWCLiveActivityBridge). UserDefaults
-        // returns 0 if the key was never written, which matches the default.
-        NSInteger persisted = [NWCLiveActivityBridge appGroupTrackIndex];
+        // Restore the user's preferred track. Preference key wins; fall back
+        // to the display-state index (which reflects in-session changes made
+        // from the Dynamic Island) if the user never picked in settings.
+        NSInteger fallback = [NWCLiveActivityBridge appGroupTrackIndex];
+        NSInteger persisted = [NWCLiveActivityBridge preferredTrackIndexWithFallback:fallback];
         NSInteger count = (NSInteger)_trackNames.count;
         _currentTrackIndex = (count > 0 && persisted >= 0 && persisted < count)
             ? persisted
@@ -258,8 +259,10 @@ RCT_EXPORT_METHOD(setTrack:(NSInteger)index
 
 // Updates the preferred track without restarting playback. Used when the
 // settings UI changes selection during an active NWC session — the user's
-// pick should persist (app group, in-memory) so the next start uses it,
-// but the currently playing ambient track must not be interrupted.
+// pick should persist so the next start uses it, but the currently playing
+// ambient track and the Dynamic Island must not be interrupted. Writes only
+// the preference key in the app group; the display-state index (which the
+// Live Activity refresh timer reads every 15s) is intentionally left alone.
 RCT_EXPORT_METHOD(setTrackPreference:(NSInteger)index
                   resolver:(RCTPromiseResolveBlock)resolve
                   rejecter:(RCTPromiseRejectBlock)reject) {
@@ -268,9 +271,7 @@ RCT_EXPORT_METHOD(setTrackPreference:(NSInteger)index
         return;
     }
 
-    self.currentTrackIndex = index;
-    [NWCLiveActivityBridge syncAppGroupFromAudioWithTrackIndex:index
-                                                      isMuted:self.isMuted];
+    [NWCLiveActivityBridge setPreferredTrackIndex:index];
 
     resolve([self currentStatusDict]);
 }
@@ -345,6 +346,7 @@ RCT_EXPORT_METHOD(disarmNWCAudio:(RCTPromiseResolveBlock)resolve
 
     [NWCLiveActivityBridge syncAppGroupFromAudioWithTrackIndex:index
                                                       isMuted:self.isMuted];
+    [NWCLiveActivityBridge setPreferredTrackIndex:index];
 
     if (@available(iOS 16.1, *)) {
         NSString *trackName = self.trackNames[index];

ios/zeus/NWCLiveActivityBridge.swift

@@ -19,4 +19,18 @@ import Foundation
             revision: revision
         )
     }
+
+    /// Returns the persisted preferred track index, or `fallback` if unset.
+    /// Distinct from the display-state track index so the Live Activity
+    /// refresh timer doesn't surface the preference while a different track
+    /// is actually playing.
+    @objc(preferredTrackIndexWithFallback:)
+    static func preferredTrackIndex(fallback: Int) -> Int {
+        NWCLiveActivityShared.readPreferredTrackIndex() ?? fallback
+    }
+
+    @objc(setPreferredTrackIndex:)
+    static func setPreferredTrackIndex(_ index: Int) {
+        NWCLiveActivityShared.writePreferredTrackIndex(index)
+    }
 }