app.py

# ---------- Gradio Space entrypoint (no FastAPI/Uvicorn) ----------
import os
os.environ.setdefault("GRADIO_USE_CDN", "true")

import gradio as gr

# (Optional) ZeroGPU probe — harmless on CPU. Will work once you switch HW to ZeroGPU.
try:
    import spaces
    @spaces.GPU(duration=10)
    def gpu_probe(a: int = 1, b: int = 1):
        return a + b
except Exception:
    pass

with gr.Blocks(title="Hello Space") as demo:
    gr.Markdown("### ✅ App is alive\nType to echo.")
    inp = gr.Textbox(label="Input", value="hello")
    out = gr.Textbox(label="Output")
    inp.submit(lambda s: f"echo: {s}", inp, out)

# IMPORTANT: expose a top-level `demo`, and DO NOT call .launch()
demo = demo.queue(max_size=8)