use slider for max input token ength

app.py

@@ -108,7 +108,13 @@ 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.Number(value=500, label="Max Length (tokens)", minimum=64, maximum=2000, step=64)
+    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")