minor fix

src/palm-oil/vision.gateway.ts

@@ -205,7 +205,7 @@ export class VisionGateway
       const response = await fetch(N8N_WEBHOOK_URL, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
-        body: JSON.stringify([body]),
+        body: JSON.stringify(body),
       });
 
       const raw = await response.json();