Error from paginate_checked: next_token was present but is not a valid
offset token (not produced by a prior page of the same list op). AWS rejects
such tokens with InvalidNextToken (or a service-specific equivalent);
callers map this to their wire error (bug-audit 2026-05-28, 1.7).
Strict variant of paginate: a next_token that is present but does not
parse as a non-negative offset is rejected with InvalidNextToken instead
of being silently treated as offset 0 (which can drive an infinite client
pagination loop). None still means “first page”.