Lead guides cover leads without a sponsor

Create and export leads without a sponsor, with explicit scope and update rules.

The lead reference and create/update cookbook now explain how to create a lead with an omitted or null sponsor_id, how sponsor-restricted scopes choose a sponsor, and why omitting the field on PATCH preserves existing ownership.

The export guide covers event exports that include leads with sponsor-ids: [] and explains why sponsor filters and sponsor-restricted scopes exclude those leads.

The updated export guidance is also included in version 1.1.1 of the agent skill bundle. Replace an installed copy to use the revised bundled reference.