Add an in-memory SendLimiter enforcing a one-per-minute cooldown and a
five-per-rolling-hour cap per recipient address, checked before provisioning or
sending in RequestCode, RequestLoginCode and RequestLinkCode. It guards against
email bombing and protects the relay quota. The limiter is injected in main
(nil in tests, so the domain suite is unaffected); ErrTooManyRequests maps to
HTTP 429.
Swap the net/smtp mailer for go-mail behind the existing Mailer seam: the
Message struct now carries a text + HTML body, TLS mode is chosen from the port
(implicit TLS on 465, else mandatory STARTTLS), a dial timeout bounds the
synchronous send, and no client certificate is needed. Add a branded, image-free,
mobile-friendly ru/en HTML template (with a plain-text alternative) rendering a
large readable code and an ignore-notice footer with a landing link.
Add BACKEND_PUBLIC_BASE_URL config (the canonical origin for the email footer
link, never the request Host — anti-injection), required when a relay is
configured.
Fix the email-login address squat: ProvisionEmail creates the account flagged
is_guest until the code is confirmed, so an abandoned login is reaped like any
guest and its address freed; confirming (login or link) clears the flag. Seed the
new account's language from the client, plumbed through the email-login request.
The confirm deeplink, its transport surface and the send rate-limit land in
follow-up work.
Ilia Denisov
developer