feat(service): NestJS kernel skeleton + 10-table kernel schema (P1.1+1.2)

Reuses support-service bootstrap/health/prisma patterns. Kernel-only Prisma
schema (scope/source_handle/actor/channel/thread/participant/interaction/
message_part/outbox/processed_event) with orgId/appId NOT NULL and
@@unique([scopeId, idempotencyKey]). Health verified: {status:ok,db:true}.

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

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

@@ -0,0 +1,19 @@
+import { Controller, Get } from '@nestjs/common';
+import { PrismaService } from './prisma/prisma.service';
+
+@Controller('health')
+export class HealthController {
+  constructor(private readonly prisma: PrismaService) {}
+
+  @Get()
+  async check(): Promise<{ status: string; db: boolean }> {
+    let db = false;
+    try {
+      await this.prisma.$queryRaw`SELECT 1`;
+      db = true;
+    } catch {
+      db = false;
+    }
+    return { status: 'ok', db };
+  }
+}