add scroll top to thinking box

Author: commit111

samples/agentic-strands/app/index.html

@@ -108,6 +108,7 @@ <h1>Library Assistant AI</h1>
                     loadingDiv.className = 'message agent-message loading';
                     loadingDiv.textContent = 'Thinking...';
                     chatContainer.appendChild(loadingDiv);
+                    chatContainer.scrollTop = chatContainer.scrollHeight;
 
                     try {
                         const response = await fetch('/chat', {