feat(ads): add headline image style option for local native ad widget

- Introduce HeadlineImageStyle enum to determine ad's visual size
- Adjust image height based on headlineImageStyle preference
- Add headlineImageStyle parameter to LocalNativeAdWidget constructor

Author: fulleni

lib/ads/widgets/local_native_ad_widget.dart

@@ -7,14 +7,27 @@ import 'package:ui_kit/ui_kit.dart';
 /// {@endtemplate}
 class LocalNativeAdWidget extends StatelessWidget {
   /// {@macro local_native_ad_widget}
-  const LocalNativeAdWidget({required this.localNativeAd, super.key});
+  const LocalNativeAdWidget({
+    required this.localNativeAd,
+    this.headlineImageStyle,
+    super.key,
+  });
 
   /// The [LocalNativeAd] to display.
   final LocalNativeAd localNativeAd;
 
+  /// The user's preference for feed layout, used to determine the ad's visual size.
+  final HeadlineImageStyle? headlineImageStyle;
+
   @override
   Widget build(BuildContext context) {
     final theme = Theme.of(context);
+
+    // Determine the height based on the headlineImageStyle.
+    // If largeThumbnail, use a square aspect ratio, otherwise a standard native ad height.
+    final double imageHeight =
+        headlineImageStyle == HeadlineImageStyle.largeThumbnail ? 250 : 180;
+
     return Card(
       margin: const EdgeInsets.symmetric(
         horizontal: AppSpacing.paddingMedium,
@@ -31,7 +44,7 @@ class LocalNativeAdWidget extends StatelessWidget {
                 child: Image.network(
                   localNativeAd.imageUrl,
                   fit: BoxFit.cover,
-                  height: 180,
+                  height: imageHeight,
                   width: double.infinity,
                   errorBuilder: (context, error, stackTrace) =>
                       const SizedBox.shrink(),