feat(media): 图片占位改为纯色块并去掉扫光

lib/pages/recommend/widgets/home_recommend_content.dart

@@ -97,7 +97,6 @@ class HomePosterCard extends StatelessWidget {
                   RemoteImage(
                     drama.posterUrl,
                     fit: BoxFit.cover,
-                    showFallbackIcon: true,
                     fallbackColor: AppColors.contentSurface,
                   ),
                   if (tagLabel.isNotEmpty)
@@ -189,7 +188,6 @@ class HomeEditorPickBanner extends StatelessWidget {
               RemoteImage(
                 drama.posterUrl,
                 fit: BoxFit.cover,
-                showFallbackIcon: true,
                 fallbackColor: AppColors.contentSurface,
               ),
               const DecoratedBox(