fix: Remove theme parameter for Gradio 6 compatibility

Gradio 6.0.0.dev4 has API changes where gr.Blocks() no longer accepts
theme parameter in the same way as Gradio 5.

Error was:
TypeError: BlockContext.__init__() got an unexpected keyword argument 'theme'

Fix: Removed theme=gr.themes.Soft() parameter from gr.Blocks()

The app will use default theme for now. Can revisit theming once
Gradio 6 API is more stable.

app.py

@@ -35,7 +35,8 @@ except ValueError:
 def create_gradio_ui():
     """Create Gradio UI for testing MCP tools"""
 
-    with gr.Blocks(title="TraceMind MCP Server", theme=gr.themes.Soft()) as demo:
+    # Note: Gradio 6 has different theme API
+    with gr.Blocks(title="TraceMind MCP Server") as demo:
         gr.Markdown("""
         # 🤖 TraceMind MCP Server