[model] add deepseek-R1 & show think process (#6767)

Former-commit-id: 4dccb724af51208a001c96fefbdbf226be09e50c

src/llamafactory/webui/chatter.py

@@ -157,6 +157,7 @@ class WebChatModel(ChatModel):
             top_p=top_p,
             temperature=temperature,
         ):
+            new_text = '' if any(t in new_text for t in ('<think>', '</think>')) else new_text
             response += new_text
             if tools:
                 result = self.engine.template.extract_tool(response)