@zeitverschreib@snarfed.org@snarfed.org (a) the hashtag goes in your bio (b) that's not going to change, they're being nice, the norm is that bridges don't ask and the only way to have a say at all is to just block the bridge... which you can always do.
If you feel like your content needs to be opt-in to distribute, you should set all your posts private (bridge will only see them if you accept a follow request from a Bluesky user on the bridge), or you should move to a whitelist server (where your posts will only federate to explicitly approved servers)