Use profullstack.com/motd as the shared Message of the Day across both
the SSH BBS hub and the Ergo IRC server.
- internal/motd: fetch + in-memory cache with background refresh (stdlib
only); Current() never blocks session start, keeps last value on error.
Source overridable via AGENTBBS_MOTD_URL.
- hub: append the daily MOTD below the existing welcome/onboarding text.
- IRC: deploy/ergo/refresh-motd.sh pulls /motd into Ergo's ergo.motd and
rehashes; setup.sh installs it + an ergo-motd.timer (hourly) mirroring
the ergo-certs timer, with a seeded fallback if the source is offline.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
