Add ZeroGPU entry point for the generation tier

ZeroGPU refuses to start without a @spaces.GPU function. The decorated
generate_mesh is reserved for text-to-3D and is not called yet.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app.py

@@ -9,6 +9,7 @@ import re
 import tempfile
 import threading
 
+import spaces  # ZeroGPU: import before any CUDA-touching library
 import gradio as gr
 
 from vli import assets, pipeline, scene, simplify, vlm
@@ -22,6 +23,16 @@ def _fail(e):
     raise gr.Error(str(e))
 
 
+@spaces.GPU(duration=60)
+def generate_mesh(prompt):
+    """GPU entry point for the generation tier (last in the fallback chain).
+
+    ZeroGPU needs a @spaces.GPU function at startup. Nothing calls this until
+    text-to-3D is wired in, so no quota is used.
+    """
+    raise NotImplementedError("generation tier is not wired up yet")
+
+
 # ---------------- MCP tools ----------------
 
 def check_words(sentence: str, primitives_json: str = "{}") -> str:

requirements.txt

@@ -1,3 +1,4 @@
+spaces
 gradio[mcp]
 huggingface_hub
 requests