Improve back-pressure `Ticket` pressure across lifecycle cross components

Right now the node eagerly drops tickets potentially too early in the process. To make it reflect actual load more accurately, we should ensure that a `Ticket` from processing a request is dropped exactly when all of its resource use has concluded.

Whether it is feasible to drop the `Ticket` approach entirely in favor of making proper request-response patterns offered by `juliet` fixing this issue remains a matter of scope.