refactor: 统一 workflow 卡片状态为可编辑

- 将所有 workflow 卡片的 isCompleted 设置为 false
- 输入框保持可输入状态（除非正在提交）
- 按钮统一显示提交状态
- 为后续添加完成状态逻辑做准备

src/pages/Chat/components/ChatItem/ChatAnswerAttchment.tsx

@@ -177,7 +177,7 @@ export const ChatAnswerAttachment: React.FC<ChatAnswerAttachmentProps> = ({
                       answer={answer}
                       onSubmitWorkflow={onWorkflowSubmit || (() => {})}
                       isSubmitting={isWorkflowSubmitting}
-                      isCompleted={!isLastAnswer}
+                      isCompleted={false}
                     />
                   )}
                   {/* 其他 card-* 类型 */}