@jamie @snarfed.org @oliphant @HistoPol @luca @PCOWandre @chronohart @snarfed a boost in this case will operate the same as with normal ActivityPub, in which case the block should remain honored. It'll be the exact same as someone boosting your post and whether someone you blocked on AP can see that post.
I'll note however that the bridge should not be a concern if you're worried about that, instead you should be concerned of the thousands of instances like mine (Friendica and Hubzilla) that will natively support Bluesky. If we boost your post, then it'll be copied over to Bluesky with no actual connection to you in the network, so your blocks will not apply and you will have no control over the post afterwards.