Add no-op @spaces.GPU probe so ZeroGPU runtime starts (app is CPU-only)

app.py

@@ -21,6 +21,26 @@ from src.tools.tool_matcher import ToolMatcher
 
 logger = logging.getLogger(__name__)
 
+# HF Spaces' free tier for Gradio is ZeroGPU, whose runtime aborts at startup ("No
+# @spaces.GPU function detected") unless at least one function is decorated with
+# @spaces.GPU. This app is CPU-only (all inference is via the OpenAI API), so we only
+# need the decorator to EXIST — the probe below is never called. `spaces` isn't a local
+# dev dependency (HF injects it in the Space build), so fall back to a no-op decorator.
+try:
+    import spaces  # provided by the HF ZeroGPU runtime
+
+    _gpu = spaces.GPU
+except Exception:  # local / non-ZeroGPU: `spaces` not installed
+    def _gpu(fn=None, **_kwargs):
+        return fn if callable(fn) else (lambda f: f)
+
+
+@_gpu
+def _zero_gpu_probe():
+    """Exists solely so ZeroGPU detects a @spaces.GPU function at startup; unused."""
+    return None
+
+
 # Built once per process, not per session — these load models and are the cold-start cost.
 accounts = AccountsService()
 tool_matcher = ToolMatcher()