Are worker honeybees aware they will likely die after stinging and, if so, is this awareness designed as a kind of karmic regulator, to discourage honeybees from stinging unless the need to do so is truly imperative?

This was designed as a karmic regulator to be a check on the level of injury that could be inflicted by bees over time, but it is not in the conscious awareness of the bee such that they must choose to sacrifice themselves in order to use their stinger. It is part of the inner workings that the instinct will be one of caution unless there is a certain level of arousal from perceived danger. That, too, is a predesigned safeguard that will keep aggression in check unless there are compelling signs it is appropriate to use the stinger, and then the bees will not hesitate out of concern for personal safety. They will be unaware of what will happen to them, but we can assure you that the way this was designed was purposeful and demonstrates Creator’s wisdom in wanting the bees to fit in and be good neighbors to humans and, indeed, a kind of partner for them to have access to the benefits of honey without inordinate risk to personal wellbeing. So the fact bees are, by and large, gentle creatures almost all of the time works to benefit humanity more than the bees themselves.