feat(service): outbox relay + thread read endpoint + replay (P1.5, P1 complete)

OutboxRelay: FOR UPDATE SKIP LOCKED claim, in-process bus publish, PENDING->
PUBLISHED with 30s backoff + idempotent-consumer ledger. GET /v1/threads/:id/
messages (policy-scoped). Replay + read specs green; vitest fileParallelism off
(shared DB). End-to-end HTTP smoke verified: idempotent ingest, read-back, 400
on missing key. 19 tests pass.

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

packages/iios-service/src/threads/threads.controller.ts

@@ -0,0 +1,12 @@
+import { Controller, Get, Param } from '@nestjs/common';
+import { ThreadsService } from './threads.service';
+
+@Controller('v1/threads')
+export class ThreadsController {
+  constructor(private readonly threads: ThreadsService) {}
+
+  @Get(':id/messages')
+  async messages(@Param('id') id: string) {
+    return this.threads.getMessages(id);
+  }
+}