Fix IndexError when model list is empty at startup

Guard against empty get_available_models() result; print error for diagnosis.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app.py

@@ -142,8 +142,9 @@ def init_interface(opt, *args, **kwargs) -> None:
                     pad_scale = gr.Slider(label="Reference padding scale", minimum=1, maximum=2, value=1, step=0.05)
 
                 with gr.Row():
-                    sd_model = gr.Dropdown(choices=get_available_models(), label="Models",
-                                           value=get_available_models()[0])
+                    available_models = get_available_models()
+                    sd_model = gr.Dropdown(choices=available_models, label="Models",
+                                           value=available_models[0] if available_models else None)
                     extractor_model = gr.Dropdown(choices=line_extractor_list,
                                               label="Line extractor", value=default_line_extractor)
                     mask_model = gr.Dropdown(choices=mask_extractor_list, label="Reference mask extractor",

backend/appfunc.py

@@ -37,7 +37,8 @@ def get_available_models():
     try:
         files = list_repo_files(HF_REPO_ID)
         return [f for f in files if f.endswith(".safetensors")]
-    except Exception:
+    except Exception as e:
+        print(f"Failed to list models from {HF_REPO_ID}: {e}")
         return []