fix: 剧本查询时自动为历史剧本补建 conversation（兼容前端临时 ID）

server/src/main/java/com/emotion/service/impl/EpicScriptServiceImpl.java

@@ -147,7 +147,12 @@ public class EpicScriptServiceImpl extends ServiceImpl<EpicScriptMapper, EpicScr
                 .eq(EpicScript::getIsDeleted, 0)
                 .orderByDesc(EpicScript::getCreateTime);
 
-        return this.list(wrapper).stream()
+        List<EpicScript> scripts = this.list(wrapper);
+        for (EpicScript script : scripts) {
+            ensureConversationForScript(script, currentUserId);
+        }
+
+        return scripts.stream()
                 .map(this::convertToResponse)
                 .collect(Collectors.toList());
     }
@@ -165,6 +170,9 @@ public class EpicScriptServiceImpl extends ServiceImpl<EpicScriptMapper, EpicScr
             return null;
         }
 
+        // 历史剧本兼容：conversation 不存在时自动创建
+        ensureConversationForScript(script, currentUserId);
+
         return convertToResponse(script);
     }
 
@@ -775,4 +783,38 @@ public class EpicScriptServiceImpl extends ServiceImpl<EpicScriptMapper, EpicScr
         }
         return response;
     }
+
+    /**
+     * 为剧本补建 conversation（历史剧本兼容）
+     *
+     * 触发条件：script.conversationId 指向的 conversation 不存在（DB 中无对应记录）
+     * 副作用：创建新 conversation，回填 script.conversationId，更新 script
+     */
+    private void ensureConversationForScript(EpicScript script, String currentUserId) {
+        String conversationId = script.getConversationId();
+        if (!org.springframework.util.StringUtils.hasText(conversationId)) {
+            // conversationId 字段本身为空，直接创建
+            createAndAttachConversation(script, currentUserId);
+            return;
+        }
+        Conversation existing = conversationService.getById(conversationId);
+        if (existing != null) {
+            return; // 已存在，无需处理
+        }
+        // 存在 conversationId 但 conversation 不存在（历史数据），创建新的
+        createAndAttachConversation(script, currentUserId);
+    }
+
+    private void createAndAttachConversation(EpicScript script, String currentUserId) {
+        Conversation conversation = new Conversation();
+        conversation.setUserId(currentUserId);
+        conversation.setScriptId(script.getId());
+        conversation.setTitle(script.getTitle() != null ? script.getTitle() : "未命名剧本");
+        conversation.setType("script");
+        conversation.setConversationStatus("active");
+        conversationService.save(conversation);
+
+        script.setConversationId(conversation.getId());
+        this.updateById(script);
+    }
 }