/// cursor 分页正典信封 `{items, nextCursor, hasMore}`（pets 域体重 / 健康事件，
/// community 域 Feed / 我的帖子 / 评论 / 收藏共用；自 pet_models.dart 上移至 core）。
class CursorPage<T> {
  const CursorPage({
    required this.items,
    required this.nextCursor,
    required this.hasMore,
  });

  factory CursorPage.fromJson(
    Map<String, dynamic> json,
    T Function(Map<String, dynamic>) itemFromJson,
  ) {
    return CursorPage(
      items: (json['items'] as List)
          .map((item) => itemFromJson(item as Map<String, dynamic>))
          .toList(),
      // 不透明 base64url 游标，客户端不得解析；hasMore=false 时恒为 null。
      nextCursor: json['nextCursor'] as String?,
      hasMore: json['hasMore'] as bool,
    );
  }

  final List<T> items;
  final String? nextCursor;
  final bool hasMore;
}