feat: Authors feature backend (and upgraded deprecated mods)

api/handlers/media/purgeHandler.go

@@ -54,6 +54,7 @@ type purgeRunResponse struct {
 	Merged          int `json:"merged"`
 	ArticlesUpdated int `json:"articles_updated"`
 	SitesUpdated    int `json:"sites_updated"`
+	AuthorsUpdated  int `json:"authors_updated"`
 	FailedGroups    int `json:"failed_groups"`
 }
 
@@ -166,6 +167,7 @@ func (h *Handler) RunPurge(w http.ResponseWriter, r *http.Request) {
 		Merged:          result.Merged,
 		ArticlesUpdated: result.ArticlesUpdated,
 		SitesUpdated:    result.SitesUpdated,
+		AuthorsUpdated:  result.AuthorsUpdated,
 		FailedGroups:    result.FailedGroups,
 	})
 }