fix: Improve thinking tag removal with more aggressive cleaning

- Add multiple regex passes to handle various think tag scenarios
- Remove standalone <think> and </think> tags that might remain
- Clean leading whitespace after tag removal
- Add debug logging to track text cleaning process
- Handle streaming cases where tags appear before closing tags arrive

This provides more robust cleaning to ensure no think tags appear
in the final message content during streaming scenarios.

examples/chat-ui/src/components/ChatMessage.tsx

@@ -34,7 +34,7 @@ const ChatMessage: React.FC<ChatMessageProps> = ({
         className={` 
         ${
           message.role === "user"
-            ? "max-w-[80%] rounded-2xl px-3 py-2 border border-zinc-200/10 bg-zinc-100 text-black"
+            ? "max-w-[80%] rounded-2xl px-3 py-2 border border-zinc-200/10 bg-white text-black"
             : " text-zinc-900 w-full"
         }`}
       >