Durable GC for stale bridge registrations (TTL prune) - no more retired-codex corpses in registrations.json

MSG-221 llmmsg-srv Deferred

lezama ca.sh deploy: GCABA box - get Elazar explicit OK before nw-lezama-cc syncs; codex AGENTS.md convention (aro_join on start, cm/cms -> read_unread)

MSG-190 llmmsg-srv Deferred ↳ MSG-186

Rationalize errscan-vs-applog overlap fleet-wide (both = error->PM-DM; applog covers all 3 proj+now green, errscan mars-only, mars DOUBLE-covered) - decide consolidate-not-expand; needs PM/Elazar division-of-labor call

MSG-43 llmmsg-srv Deferred low