Failing tests first (3 red: a redelivered activity reran its behavior — behavior/process starts
from an empty trace, so dedup evaporated per call). host/blog--process-local! now atomically
claims the :id on persist stream 'activities:processed' via ev/book! (the same append-expect
acquire as seats/votes) and returns a :deduped trace on duplicates. Store-backed → survives outbox
retries AND restarts. Prerequisite for non-idempotent effects (payment). Id-less activities process
unchecked.
blog suite 250/250 (+3).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>