We could show you your pubkey in your profile (such that only you can see it) but currently, we don't do that. I created a ticket for that: https://github.com/stackernews/stacker.news/issues/281
Actually, I forgot how LNURL-auth works, lol
We do not receive the pubkey of your wallet. It's a domain-specific key. So my proposed solution wouldn't work.
See discussion here: https://github.com/stackernews/stacker.news/pull/282
How to check wich wallet you are connected with?