#3212 fix：

1.修复RAGFlow连接异常导致级联删除问题
2.修复RAGFlow获取数量逻辑问题
3.远程失败不再删除本地影子记录，避免产生RAGFlow端孤儿文档
4.优化前端提示语

main/manager-web/src/views/KnowledgeBaseItem.vue

@@ -217,9 +217,9 @@ export default {
           } else {
             this.$message.error(res.data?.msg || this.$t('knowledgeFileUpload.deleteFailed'));
           }
-        }, () => {
+        }, (err) => {
           this.$set(this.deleteLoadingMap, doc.id, false);
-          this.$message.error(this.$t('knowledgeFileUpload.deleteFailed'));
+          this.$message.error(err?.data?.msg ||this.$t('knowledgeFileUpload.deleteFailed'));
         });
       }).catch(() => {});
     },