List conversation previews (v3)

List the newest conversations of a campaign's results window (dated in the 30 days ending its as-of day, scope.window) as previews, at most 12, optionally narrowed to segments: each customer's name and job title or age, the assistant, when it happened, the brands it named and their role, and its first turns. Of those, the ones held in the campaign's language come first, newest first within each group: the campaign's language is its profile's, else English, and a customer who declares no language speaks it. A campaign without results answers its state and no previews. Page through and search every conversation with discovery_conversations_list_v2.