The browser skill's browser closes within seconds of its session's end

Every agent session gets its own headless browser from the browser skill, and that browser closes when the session ends. On a busy machine it used to linger for ten seconds or more, because the skill waited for Chrome's orderly shutdown. Now Chrome gets a two-second grace, then it is ended hard and its temporary profile removed, so a session's browser is gone within about three seconds even when the machine is loaded.