gateway: diff the Gateway resources server-side

The API server fills in Gateway API defaults such as the parentRef group and kind and a PathPrefix / match, so Argo CD's client-side diff kept gateway-folder OutOfSync.

apps/templates/gateway-folder.yaml

@@ -3,6 +3,10 @@ kind: Application
 metadata:
   name: gateway-folder
   namespace: argocd
+  annotations:
+    # Let the API server fill in Gateway API defaults before diffing, or
+    # every defaulted field shows up as a difference.
+    argocd.argoproj.io/compare-options: ServerSideDiff=true
   finalizers:
   - resources-finalizer.argocd.argoproj.io
 spec: