Fix Gradio messages format for updated HF Spaces

- HF Spaces now uses newer Gradio requiring messages format
- Added try/except for type="messages" parameter with fallback
- Changed chat history to dict format with role/content keys
- Fixes: "Data incompatible with messages format" error

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

app.py

@@ -170,7 +170,12 @@ def chat(message, history):
 with gr.Blocks() as demo:
     gr.Markdown(f"# MedRAX2 - Medical AI Assistant\n**Device:** {device} | **Tools:** {len(tools)} loaded | **Orchestrator:** Gemini 2.0 Flash")
 
-    chatbot = gr.Chatbot()
+    # Use type="messages" for newer Gradio versions on HF Spaces
+    try:
+        chatbot = gr.Chatbot(type="messages")
+    except TypeError:
+        # Fallback for older Gradio versions
+        chatbot = gr.Chatbot()
     viz_output = gr.Image(label="Grounding Visualization", visible=True)
 
     msg = gr.MultimodalTextbox(
@@ -189,11 +194,13 @@ with gr.Blocks() as demo:
         else:
             text = message
 
-        # Add to chat history - use list of pairs format for older Gradio
+        # Add to chat history - use messages format for newer Gradio
         if chat_history is None:
             chat_history = []
 
-        chat_history.append([text, bot_message])
+        # Use dict format with role/content for messages type chatbot
+        chat_history.append({"role": "user", "content": text})
+        chat_history.append({"role": "assistant", "content": bot_message})
 
         return "", chat_history, viz_image