bool isstale:Add bool isstale to store.dart

Author: satyam372

pubspec.yaml

@@ -27,6 +27,7 @@ environment:
   sdk: '>=3.5.0-90.0.dev <4.0.0'
   flutter: '>=3.22.0-16.0.pre.20'
 
+
 # Dependencies specify other packages that your package needs in order to work.
 # To automatically upgrade your package dependencies to the latest versions
 # consider running `flutter pub upgrade --major-versions`. Alternatively,