Very nice article. This was the intro I needed having not yet looked closely at LNURL.
However, when you say "your wallet will translate that into URL https://stacker.news/.well-known/lnurlp/heisenberg", do you mean there's an actual process of discovery not here described, or that the LNURL is a convention meaning that all websites serving LNURLs must follow this pattern so wallets can safely assume the final URL based on the username format?
In LNURL-pay in general, the URL (encoded with bech32 encoding in QR code) can be anything, for example https://server.com/anythinghere.
In Lightning Address (subset of LNURL-pay), final URL is ALWAYS ".../.well-known/lnurlp/<username>".