Add an entity-scoped attention capability: the subject is resolved to a
canonical Nexus entity_id, the id travels to Praxis as a query scope
instead of being dropped after resolution, and Maven's own facts already
tagged with the same id join the answer. Ambiguous, unknown, degraded and
no-Nexus cases each get a distinct reply and never a scoped query without
a scope.
Give the fact-enrichment worker per-fact exponential backoff capped at an
hour and a status report of pending/in-backoff/worst-attempt counts, so a
long Nexus outage shows as a visible backlog rather than facts that
silently never got tagged. Nothing is ever given up on.
kami