feat(p7): AI tables + enums + migration + events + InferencePort contract

Task 7.1: 7 AI-proposal-layer tables (IiosAiJob, IiosAiModelRun, IiosAiArtifact,
IiosAiClaim, IiosAiEvidenceLink, IiosAiToolCall, IiosEmbeddingRef) + enums;
migration ai-init. Adds ai.job.created / ai.artifact.proposed / ai.artifact.accepted
events and a standalone InferencePort contract (not part of sealed IiosPlatformPorts).
resetDb truncates the new tables.

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

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

@@ -8,6 +8,7 @@ import type { PrismaClient } from '@prisma/client';
 export async function resetDb(prisma: PrismaClient): Promise<void> {
   await prisma.$executeRawUnsafe(
     `TRUNCATE TABLE
+      "IiosAiEvidenceLink","IiosAiClaim","IiosAiToolCall","IiosAiArtifact","IiosAiModelRun","IiosAiJob","IiosEmbeddingRef",
       "IiosRouteDecision","IiosRouteBinding","IiosModerationFlag",
       "IiosInboundRawEvent","IiosDeliveryAttempt","IiosOutboundCommand","IiosRateLimitBucket",
       "IiosTicketStateHistory","IiosTicketThreadLink","IiosCallbackRequest","IiosTicket",