fix(desktop): fix ChatArea TSx type narrowing for toolSteps and subtasks

unknown→ unknown

 ReactNode

error

desktop/src/components/ChatArea.tsx

@@ -644,16 +644,16 @@ function MessageBubble({ message, setInput }: { message: Message; setInput: (tex
               />
             )}
             {/* Tool call steps chain (DeerFlow-inspired) */}
-            {!isUser && message.toolSteps && message.toolSteps.length > 0 && (
+            {!isUser && message.toolSteps != null && message.toolSteps.length > 0 ? (
               <ToolCallChain
                 steps={message.toolSteps}
                 isStreaming={message.streaming}
               />
-            )}
+            ) : null}
             {/* Subtask tracking (DeerFlow-inspired) */}
-            {!isUser && message.subtasks && message.subtasks.length > 0 && (
+            {!isUser && message.subtasks != null && message.subtasks.length > 0 ? (
               <TaskProgress tasks={message.subtasks} className="mb-3" />
-            )}
+            ) : null}
             {/* Message content with streaming support */}
             <div className={`leading-relaxed ${isUser ? 'text-white whitespace-pre-wrap' : 'text-gray-700 dark:text-gray-200'}`}>
               {message.content