Create a group chat

Creates a group conversation between your organization and many creators, and posts a notice that the group was created, which notifies its members. groupKind decides who is in it: manual takes the hand-picked orgCreatorIds (changed later through POST|DELETE /chat/groups/{chatId}/members), campaign follows the roster of campaignId, all includes every active creator — both update on their own. title is the internal name, unique in your organization and never shown to creators; publicTitle is the name creators see. Creators not yet invited to the platform stay on the roster and see the group once invited.