ZITADEL sends verification codes and password resets by SMTP only, and this
cluster has no mail path. Every human user therefore sits at
verified_email = empty and can never finish a first login, at ZITADEL or at
Forgejo.
Add an smtp-gotify relay in the iam namespace: it accepts plain SMTP on :2525
and forwards each message to the existing Gotify instance, so codes arrive on
the phone through gotify/igotify instead of email.
Point DefaultInstance.SMTPConfiguration at that Service with TLS off, because
the relay speaks plain SMTP inside the cluster. The relay holds the Gotify app
token in a SOPS-encrypted Secret; values never carry the token.