New adminalert worker polls for feedback + word complaints arriving since the last check
and coalesces a burst into one digest email per interval (5 min), inert unless a distinct
admin sender (BACKEND_SMTP_ADMIN_FROM) and recipient (BACKEND_ADMIN_EMAIL, comma-separated
allowed) are configured. The mailer gains a per-message From override and splits a
comma-separated To into separate recipients (go-mail needs them as a list). Feedback/game
stores gain CountSince/CountComplaintsSince. Unit tests cover the digest, the skip-when-
empty, and the recipient split.
The 465-only implicit-TLS heuristic mis-classified Selectel's SSL port (1127),
which the mailer would have dialled with STARTTLS and failed. Add BACKEND_SMTP_TLS
(ssl|starttls) — empty still derives the mode from the port (implicit on 465, else
STARTTLS) — and dial implicit TLS with WithSSL()+WithPort so any port works, not
just 465. Wire SMTP_RELAY_TLS through compose/ci/prod/.env.example and document it
(Selectel: 1127 = SSL, 1126 = STARTTLS). Unit-tested.