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/prisma/prisma.module.ts

@@ -0,0 +1,9 @@
+import { Global, Module } from '@nestjs/common';
+import { PrismaService } from './prisma.service';
+
+@Global()
+@Module({
+  providers: [PrismaService],
+  exports: [PrismaService],
+})
+export class PrismaModule {}

packages/iios-service/src/prisma/prisma.service.ts

@@ -0,0 +1,9 @@
+import { Injectable, OnModuleInit } from '@nestjs/common';
+import { PrismaClient } from '@prisma/client';
+
+@Injectable()
+export class PrismaService extends PrismaClient implements OnModuleInit {
+  async onModuleInit(): Promise<void> {
+    await this.$connect();
+  }
+}