use slider for max input token ength selection

app.py

@@ -108,13 +108,7 @@ with gr.Blocks() as demo:
     # Inputs
     prompt_in = gr.Textbox(label="Prompt").harp_required(True)
     temperature_in = gr.Slider(minimum=0.8, maximum=1.1, value=0.9, step=0.1, label="Temperature", interactive=True)
-    maxlen_in = gr.Slider(
-+        minimum=500,
-+        maximum=1500,
-+        step=100,
-+        value=500,
-+        label="Max Length"
-+    )
+    maxlen_in = gr.Slider(minimum=500, maximum=1500, step=100, value=500, label="Max Length")
 
     # Outputs (JSON FIRST for HARP, then MIDI)
     labels_out = gr.JSON(label="Labels / Metadata")