feat(media): 图片占位改为纯色块并去掉扫光

lib/pages/discover/widgets/feed_banner_carousel.dart

@@ -176,7 +176,7 @@ class _FeedBannerCarouselState extends State<FeedBannerCarousel> {
       child: Stack(
         fit: StackFit.expand,
         children: [
-          RemoteImage(banner.imageUrl, showFallbackIcon: true),
+          RemoteImage(banner.imageUrl),
           DecoratedBox(
             decoration: BoxDecoration(
               gradient: LinearGradient(

lib/pages/discover/widgets/search_result_card.dart

@@ -37,7 +37,6 @@ class SearchResultCard extends StatelessWidget {
                     RemoteImage(
                       drama.posterUrl,
                       fit: BoxFit.cover,
-                      showFallbackIcon: true,
                       fallbackColor: AppColors.contentSurface,
                     ),
                     const Positioned(
@@ -60,7 +59,9 @@ class SearchResultCard extends StatelessWidget {
             ),
             const SizedBox(height: AppDimens.searchResultTitleGap),
             Text(
-              drama.localizedTitle(Localizations.localeOf(context).languageCode),
+              drama.localizedTitle(
+                Localizations.localeOf(context).languageCode,
+              ),
               key: Key('search-result-title-${drama.id}'),
               maxLines: 2,
               overflow: TextOverflow.ellipsis,
@@ -93,7 +94,9 @@ class SearchResultCard extends StatelessWidget {
   }
 
   List<String> _tags(BuildContext context) {
-    final localized = drama.localizedTypeLabels(Localizations.localeOf(context).languageCode);
+    final localized = drama.localizedTypeLabels(
+      Localizations.localeOf(context).languageCode,
+    );
     if (localized.isNotEmpty) return localized.take(3).toList(growable: false);
     final seen = <String>{};
     return [drama.genre, drama.category]