Projectors register a replay handler and route bus errors to
dlq.onConsumerFailure (dead-letter + clear the claim-then-fail claim)
instead of swallowing them. Relay dead-letters an outbox event after
IIOS_OUTBOX_MAX_ATTEMPTS instead of retrying forever. Chaos test proves
poison → DLQ → replay resolves while sibling events keep flowing (KG-13/KG-06).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Event-driven projector creates/collapses NEEDS_REPLY items from message.sent
(traceId propagated; inbox.item.created emitted) and resolves them to DONE on
message.read; idempotent via processed-event ledger. markRead now emits a
message.read outbox event (atomic). OutboxRelay runs on a 500ms timer in the
app (off in tests). Shared resetDb (TRUNCATE CASCADE) fixes cross-spec FK
isolation. 32 tests green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>