fix：获取课程下一章节改为通过列表索引

src/main/java/com/peanut/modules/sociology/service/impl/CourseCatalogueChapterServiceImpl.java

@@ -86,18 +86,21 @@ public class CourseCatalogueChapterServiceImpl extends ServiceImpl<CourseCatalog
     @Override
     public Map<String, Object> getNextChapterDetail(Integer chapterId) {
         CourseCatalogueChapterEntity currentChapter = this.getById(chapterId);
-        if (currentChapter==null) return null;
+        if (currentChapter == null) {
+            return null;
+        }
 
-        CourseCatalogueChapterEntity nextChapter = this.getOne(
-                new LambdaQueryWrapper<CourseCatalogueChapterEntity>()
-                    .eq(CourseCatalogueChapterEntity::getCatalogueId, currentChapter.getCatalogueId())
-                        .gt(CourseCatalogueChapterEntity::getSort, currentChapter.getSort() )
-                        .orderByAsc(CourseCatalogueChapterEntity::getSort)
-                        .last("limit 1")
-        );
-        if (nextChapter==null) return null;
-
-        return getChapterDetail(nextChapter.getId());
+        // 复用目录章节列表，保证下一章顺序与列表接口完全一致
+        List<CourseCatalogueChapterEntity> chapterList = getCourseCatalogueChapterList(currentChapter.getCatalogueId());
+        for (int i = 0; i < chapterList.size(); i++) {
+            if (chapterId.equals(chapterList.get(i).getId())) {
+                if (i + 1 >= chapterList.size()) {
+                    return null;
+                }
+                return getChapterDetail(chapterList.get(i + 1).getId());
+            }
+        }
+        return null;
     }