feat(cover): 短剧新增横版封面字段并在进度接口下发

- Drama/DramaSaveReqVO/DramaRespVO 新增 horizontalCover，打通后台上传链路
- AppDramaCardVO/AppDramaDetailVO 新增 coverLandscape
- ProgressRespVO 新增 dramaCoverLandscape，继续观看横幅可直接取横版图

fruitshorts-app-api/src/main/java/com/fruitshorts/app/service/AppCatalogService.java

@@ -206,6 +206,7 @@ public class AppCatalogService {
         detail.setTitleLocales(titles);
         detail.setSynopsisLocales(synopses);
         detail.setCover(drama.getCoverUrl());
+        detail.setCoverLandscape(drama.getHorizontalCoverUrl());
         detail.setTypes(types);
         fillDetailTag(detail, drama);
         detail.setTotalEpisodes(drama.getTotalEpisodes());
@@ -348,6 +349,7 @@ public class AppCatalogService {
                 drama.getSynopsisLocales(), drama.getSynopsis(), null, null);
         card.setTitleLocales(titles);
         card.setCover(drama.getCoverUrl());
+        card.setCoverLandscape(drama.getHorizontalCoverUrl());
         card.setSynopsisLocales(shortLocales(synopses));
         card.setTypes(types);
         fillTag(card, drama, tags);

fruitshorts-app-api/src/main/java/com/fruitshorts/app/vo/AppDramaCardVO.java

@@ -15,6 +15,8 @@ public class AppDramaCardVO {
     private Long id;
     private Map<String, String> titleLocales;
     private String cover;
+    /** 横版封面（16:9），横幅等横向位优先用它；空串表示未上传，客户端回退竖版。 */
+    private String coverLandscape;
     private Map<String, String> synopsisLocales;
     /** 短剧选中的全部类型，每项是一份语言表。 */
     private List<Map<String, String>> types;

fruitshorts-app-api/src/main/java/com/fruitshorts/app/vo/AppDramaDetailVO.java

@@ -14,6 +14,8 @@ public class AppDramaDetailVO {
     private Map<String, String> titleLocales;
     private Map<String, String> synopsisLocales;
     private String cover;
+    /** 横版封面（16:9）；空串表示未上传。 */
+    private String coverLandscape;
     private List<Map<String, String>> types;
     private Map<String, String> tagLocales;
     /** 标签语义码，如 NEW_ARRIVAL；空表示未配置。 */