Add back @spaces.GPU touch required by ZeroGPU runtime

app.py

@@ -21,6 +21,19 @@ if hf_token:
     login(token=hf_token)
 
 
+# ZeroGPU Spaces require at least one @spaces.GPU function to be defined
+# during startup.  This minimal touch satisfies that requirement.
+@spaces.GPU(duration=1)
+def _gpu_startup_touch():
+    return "ok"
+
+
+try:
+    _gpu_startup_touch()
+except Exception as e:
+    print(f"Warning: ZeroGPU touch failed: {e}", flush=True)
+
+
 def _log(message):
     print(message.encode("ascii", "backslashreplace").decode("ascii"), flush=True)