feat: 会商链条启停与深度研究报告结构，并完善问答展示与 8BF 返回。

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend-web/src/components/ai-elements/reasoning.tsx

@@ -165,7 +165,7 @@ export const ReasoningTrigger = memo(
 export type ReasoningContentProps = ComponentProps<
   typeof CollapsibleContent
 > & {
-  children: string;
+  children: ReactNode;
 };
 
 export const ReasoningContent = memo(
@@ -178,7 +178,11 @@ export const ReasoningContent = memo(
       )}
       {...props}
     >
-      <Streamdown {...reasoningPlugins}>{children}</Streamdown>
+      {typeof children === "string" ? (
+        <Streamdown {...reasoningPlugins}>{children}</Streamdown>
+      ) : (
+        children
+      )}
     </CollapsibleContent>
   ),
 );