Fix FastAPI route registration

Get app reference before adding routes to ensure proper registration timing.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

app.py

@@ -215,9 +215,12 @@ with gr.Blocks(title="HuggingFace Webhook Processor") as demo:
         outputs=[status_text, message_count, batch_count, latest_batch]
     )
 
+# Get the FastAPI app instance
+app = demo.app
 
-# Add webhook endpoints to Gradio's FastAPI app (Gradio 5 method)
-@demo.app.post("/webhooks/hub")
+
+# Add webhook endpoints to FastAPI app
+@app.post("/webhooks/hub")
 async def webhook_endpoint(request: Request):
     """
     Webhook endpoint for HuggingFace Hub events.
@@ -259,7 +262,7 @@ async def webhook_endpoint(request: Request):
         raise HTTPException(status_code=500, detail=str(e))
 
 
-@demo.app.get("/webhooks/health")
+@app.get("/webhooks/health")
 async def health_check():
     """Health check endpoint."""
     with message_lock: