feat(p9): IiosDlqItem + DlqService (dead-letter + deterministic replay)

Task D.1: mandated dlq_item table (sourceType/sourceId/failureStage/errorCode/
retryCount/payloadRef/consumerName/scopeId/status). DlqService.record (idempotent
per consumer+sourceId, bumps retryCount), onConsumerFailure (quarantine + clear the
IiosProcessedEvent claim so it's replayable — fixes claim-then-fail), registerHandler
+ replay (clears claim, awaits the registered consumer handler → RESOLVED on success,
QUARANTINED+retry on repeat throw; outbox-sourced items reset to PENDING). Wired into
OutboxModule; resetDb truncates it. 3 tests.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/iios-service/src/test-utils/reset-db.ts

@@ -8,7 +8,7 @@ import type { PrismaClient } from '@prisma/client';
 export async function resetDb(prisma: PrismaClient): Promise<void> {
   await prisma.$executeRawUnsafe(
     `TRUNCATE TABLE
-      "IiosAuditLink",
+      "IiosDlqItem","IiosAuditLink",
       "IiosMeetingActionItem","IiosActionItem","IiosTranscriptSegment","IiosMeetingTranscript","IiosMeetingSummary","IiosMeetingParticipant","IiosMeeting","IiosMeetingRequest",
       "IiosCalendarSyncCursor","IiosCalendarEvent","IiosCalendarProviderAccount","IiosAvailabilityWindow",
       "IiosAiEvidenceLink","IiosAiClaim","IiosAiToolCall","IiosAiArtifact","IiosAiModelRun","IiosAiJob","IiosEmbeddingRef",