flake: Add a 'production' package The production package will be what actually goes live on https://aasg.name. At the moment, the two differences from the default package are the inclusion of Matrix-related well-known links (which only make sense on the live domain) and the Brotli compression of HTML/CSS/JS files. No more changes should happen aside from more well-known links.
nix: Add guile-json to buildInputs That GUILE_LOAD_PATH felt odd ever since I saw it again recently. guile-json not being in a build input explains why we needed it.