A curated self-serve menu: operators OFFER <host> / OFFERDEL <n>, anyone
sees OFFERLIST, and a user picks one with TAKE <n> (assigned and applied
at once). Offers are a global event-sourced list (VhostOfferAdded/Removed,
threaded through apply like bots). SETALL/DELALL alias SET/DEL and GROUP
is a no-op reassurance, since the per-account vhost already covers every
grouped nick.
