fix(entity_details): check context mount before navigating

- Add async handling to onHeadlineTap function
- Check if context is still mounted before pushing named route
- Prevent potential navigation issues due to unmounted context

Author: fulleni

lib/entity_details/view/entity_details_page.dart

@@ -227,9 +227,12 @@ class _EntityDetailsViewState extends State<EntityDetailsView> {
             ],
           );
 
-          void onHeadlineTap(Headline headline) {
-            context.read<InterstitialAdManager>().onPotentialAdTrigger();
-            context.pushNamed(
+          Future<void> onHeadlineTap(Headline headline) async {
+            await context.read<InterstitialAdManager>().onPotentialAdTrigger();
+
+            if (!context.mounted) return;
+
+            await context.pushNamed(
               Routes.globalArticleDetailsName,
               pathParameters: {'id': headline.id},
               extra: headline,