feat(service): P3.2 InboxProjector + message.read event + scheduled relay

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>

packages/iios-contracts/src/events.ts

@@ -35,6 +35,7 @@ export const IIOS_EVENTS = {
   rawReceived: 'com.insignia.iios.raw.received.v1',
   interactionNormalized: 'com.insignia.iios.interaction.normalized.v1',
   messageSent: 'com.insignia.iios.message.sent.v1',
+  messageRead: 'com.insignia.iios.message.read.v1',
   messagePersisted: 'com.insignia.iios.message.persisted.v1',
   inboxItemCreated: 'com.insignia.iios.inbox.item.created.v1',
   ticketCreated: 'com.insignia.iios.support.ticket.created.v1',