fix: harden postgresql connection on local connections

Changed files
+1 -1
systems
koumakan
services
+1 -1
systems/koumakan/services/postgresql.nix
···
authentication = ''
# unix socket connection
-
local all all trust
+
local all all pam
# local ipv4/6 tcp connection
host all all 127.0.0.1/32 scram-sha-256
host all all ::1/128 scram-sha-256