feat: add Yuheng ticket bind, trial SMS off, shared bindings

Ship ticket-exchange and bind/policy for Z13, keep trial binds SMS-free, allow shared company bindings, and align SyncPage plus sync docs.

Co-authored-by: Cursor <cursoragent@cursor.com>

platform/internal/handler/agent_sync.go

@@ -216,7 +216,7 @@ func authorizeUserOnlineDB(svcCtx *svc.ServiceContext, w http.ResponseWriter, r
 	uid := authx.UserID(r.Context())
 	tid := syncTenantID(r)
 	if !svcCtx.DBSync.Store().UserOwnsOnlineDB(tid, uid, channelID, online) {
-		authx.WriteError(w, http.StatusForbidden, "无权访问该 online_db_id（非本人 Binding）")
+		authx.WriteError(w, http.StatusForbidden, "无权访问该 online_db_id（非本人 Binding / 非公司共享库）")
 		return false
 	}
 	return true