consider using default arguments for `first` arguments

```suggestion
first: Int! = 20
```

Minor: I like to set the default in the SDL so that it's clearly visible to API consumer and so that although the argument doesnt need passed, youll always get a value in the resolver.

_Originally posted by @jdolle in https://github.com/graphql-hive/console/pull/7700#discussion_r2818975377_