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-contracts/src/index.ts

@@ -2,6 +2,7 @@ export * from './scope';
 export * from './enums';
 export * from './ingest';
 export * from './ports';
+export * from './inference';
 export * from './events';
 export * from './commands';
 export * from './errors';