List data lakes

Lists the data lakes the caller can reach as a member: lakes they own, lakes shared with them through an organization or an access grant, public lakes, and the built-in lakes their plan entitles them to. Platform-administrator reach is deliberately NOT applied here, so an admin key lists its owner's own lakes rather than every lake on the platform. Only draft and active lakes are listed. Cursor-paginated (see the pagination convention): pass next_cursor back as cursor until it is null.