fix(feed_core): use pushNamed for navigation after ad closure

- Replace context.goNamed with context.pushNamed to navigate to article details
- This change ensures proper navigation stack management after ad is closed

Author: fulleni

lib/shared/widgets/feed_core/headline_tap_handler.dart

@@ -31,7 +31,7 @@ abstract final class HeadlineTapHandler {
     if (!context.mounted) return;
 
     // Proceed with navigation after the ad is closed.
-    context.goNamed(
+    await context.pushNamed(
       Routes.articleDetailsName,
       pathParameters: {'id': headline.id},
       extra: headline,