fix: 修复 AI 消息渲染顺序错乱和搜索结果卡片重复问题

有 tool_calls 的中间 AI 消息不再渲染独立 MessageBubble 正文气泡，
thinking 内容移至 ToolCallStatus 上方作为步骤说明，
最终 AI 消息（无 tool_calls）才渲染 MessageBubble，确保工具步骤在前、正文回答在后。

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

langgraph/src/main.tsx

@@ -913,24 +913,19 @@ function App() {
               const toolCalls: { name?: string; id?: string }[] = (message as any).tool_calls ?? [];
               const isLastAi = idx === lastAiIdx;
 
+              const hasToolCalls = toolCalls.length > 0;
+
               return (
                 <div key={message.id ?? idx} className="flex flex-col gap-3">
-                  {/* Text reply — rendered first so user sees conclusion before evidence */}
-                  {(plainTextContent || hasThinking) && (
-                    <div className="group relative max-w-[85%] rounded-2xl rounded-bl-sm bg-muted text-foreground px-4 py-2.5 text-sm">
-                      <MessageBubble content={bubbleContent} role="ai" isStreaming={thread.isLoading && isLastAi} />
-                      {thread.isLoading && isLastAi && (
-                        <span className="typing-cursor" aria-hidden="true" />
-                      )}
-                      {/* Copy button */}
-                      <div className="flex justify-end mt-1">
-                        <CopyButton text={plainTextContent} />
-                      </div>
+                  {/* Tool call status (with inline expand/collapse for UI cards) */}
+                  {/* Thinking block for intermediate messages (with tool_calls): shown above tool status */}
+                  {hasThinking && hasToolCalls && (
+                    <div className="max-w-[85%]">
+                      <MessageBubble content={bubbleContent} role="ai" isStreaming={false} />
                     </div>
                   )}
 
-                  {/* Tool call status (with inline expand/collapse for UI cards) */}
-                  {toolCalls.length > 0 && (
+                  {hasToolCalls && (
                     <ToolCallStatus
                       toolCalls={toolCalls}
                       isLoading={thread.isLoading}
@@ -943,6 +938,20 @@ function App() {
                     />
                   )}
 
+                  {/* Text reply — only for final AI messages without tool_calls */}
+                  {(plainTextContent || hasThinking) && !hasToolCalls && (
+                    <div className="group relative max-w-[85%] rounded-2xl rounded-bl-sm bg-muted text-foreground px-4 py-2.5 text-sm">
+                      <MessageBubble content={bubbleContent} role="ai" isStreaming={thread.isLoading && isLastAi} />
+                      {thread.isLoading && isLastAi && (
+                        <span className="typing-cursor" aria-hidden="true" />
+                      )}
+                      {/* Copy button */}
+                      <div className="flex justify-end mt-1">
+                        <CopyButton text={plainTextContent} />
+                      </div>
+                    </div>
+                  )}
+
                   {/* UI cards not matched to any tool call (standalone) */}
                   {(() => {
                     const standaloneUiItems = uiItems.filter((ui) => !toolCalls.some((tc) => {