POST /public/v1/campaigns/{campaignId}/prospects

Add people to a campaign: everyone on a saved list (listId), the ones you choose from it (listId + prospectIds), and/or anyone by LinkedIn profile URL (linkedinUrls), up to 1000 named people per call. Owners, admins and managers may target any seat's campaign; members their own. Each person comes back with an outcome: queued, or skipped as already_in_campaign, in_another_campaign (named in detail), do_not_contact, already_contacted, not_on_list, invalid_linkedin_url or no_linkedin_profile. Queued people still pass Valley's own checks (company Do Not Contact, connection degree) before they join. An email Valley already found for someone is reused, not charged again.