fix: upgrade workmanager to 0.9.0+3 to fix Kotlin 2.x AAB build failure (#38)

lib/core/sync/background_sync.dart

@@ -38,7 +38,7 @@ Future<void> registerBackgroundSync() async {
     _kTaskName,
     frequency: const Duration(minutes: 15),
     constraints: Constraints(networkType: NetworkType.connected),
-    existingWorkPolicy: ExistingWorkPolicy.keep,
+    existingWorkPolicy: ExistingPeriodicWorkPolicy.keep,
   );
 }
 

pubspec.yaml

@@ -47,7 +47,7 @@ dependencies:
 
   # Background sync and local notifications
   flutter_local_notifications: ^18.0.1
-  workmanager: ^0.5.2
+  workmanager: ^0.9.0
 
 dev_dependencies:
   flutter_test: