feat: Add HuggingFace token login panel to Gradio interface

app.py

@@ -1108,6 +1108,41 @@ def create_interface():
         </div>
         """)
 
+        # Login Panel
+        with gr.Group():
+            gr.Markdown("### 🔐 HuggingFace Token (Optional for LLM Synthesis)")
+            with gr.Row():
+                token_input = gr.Textbox(
+                    label="HF API Token",
+                    type="password",
+                    placeholder="hf_...",
+                    scale=4,
+                )
+                login_btn = gr.Button("Login", variant="primary", scale=1)
+
+            auth_status = gr.Textbox(
+                label="Status",
+                value="Ready (token not loaded)",
+                interactive=False,
+                show_label=False,
+            )
+
+            def handle_login(token):
+                """Authenticate with HuggingFace token."""
+                if not token or token.strip() == "":
+                    return "No token provided"
+                try:
+                    login(token=token.strip())
+                    return f"✅ Authenticated! Token valid."
+                except Exception as e:
+                    return f"❌ Auth failed: {str(e)[:100]}"
+
+            login_btn.click(
+                handle_login,
+                token_input,
+                auth_status,
+            )
+
         with gr.Tabs():
             # =================== CHAT TAB ===================
             with gr.Tab("Explore", id="chat"):