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-module-content/src/main/java/com/fruitshorts/content/service/DramaService.java

@@ -464,10 +464,13 @@ public class DramaService {
         if (isNew || req.getCover() != null) {
             drama.setCoverUrl(req.getCover() == null ? "" : req.getCover());
         }
+        if (isNew || req.getHorizontalCover() != null) {
+            drama.setHorizontalCoverUrl(
+                    req.getHorizontalCover() == null ? "" : req.getHorizontalCover());
+        }
         if (isNew || req.getTrailerUrl() != null) {
             drama.setTrailerUrl(req.getTrailerUrl() == null ? "" : req.getTrailerUrl());
         }
-        drama.setHorizontalCoverUrl(drama.getHorizontalCoverUrl() == null ? "" : drama.getHorizontalCoverUrl());
         if (isNew || req.getLanguage() != null) {
             drama.setLanguage(req.getLanguage() == null ? "zh-CN" : req.getLanguage());
         }
@@ -530,6 +533,7 @@ public class DramaService {
             vo.setSynopsisLocales(synopses);
             vo.setSubtitle(drama.getSubtitle());
             vo.setCover(drama.getCoverUrl());
+            vo.setHorizontalCover(drama.getHorizontalCoverUrl());
             vo.setTrailerUrl(drama.getTrailerUrl());
             vo.setLanguage(drama.getLanguage());
             vo.setDramaType(dramaTypes.get(0));

fruitshorts-module-content/src/main/java/com/fruitshorts/content/vo/DramaRespVO.java

@@ -27,6 +27,8 @@ public class DramaRespVO {
     private String description;
     private java.util.Map<String, String> synopsisLocales;
     private String cover;
+    /** 横版封面（16:9）。 */
+    private String horizontalCover;
     /** 整剧预告片地址 */
     private String trailerUrl;
     private String language;

fruitshorts-module-content/src/main/java/com/fruitshorts/content/vo/DramaSaveReqVO.java

@@ -26,6 +26,8 @@ public class DramaSaveReqVO {
     /** 勾选语言的简介。 */
     private java.util.Map<String, String> synopsisLocales;
     private String cover;
+    /** 横版封面（16:9），用于横幅等横向位；不传则保持原值。 */
+    private String horizontalCover;
     /** 整剧预告片地址（复用已有的 drama.trailer_url 列） */
     private String trailerUrl;
     private String language;