chore: show model backend to metadata

app.py

@@ -634,6 +634,9 @@ Models:
                     )
 
                 with gr.Accordion(label="Metadata", open=False):
+                    _model_backend_md = gr.Markdown(
+                        f"Model backend: {MODEL_BACKEND}",
+                    )
                     input_prompt_raw = gr.Textbox(
                         label="Input prompt (raw)",
                         interactive=False,