feat(demo): P2.7 Vite React two-pane realtime demo + dev token endpoint (P2 complete)

apps/message-demo: Alice creates a thread, Bob joins; live two-way chat, typing,
read receipts (useMessages now exposes reads[]). Dev-only /v1/dev/token endpoint
(gated by IIOS_DEV_TOKENS) so the browser can auth. .env autoloaded (dotenv).
Realtime smoke script passes end-to-end (message + unread + receipt).

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

packages/iios-service/src/app.module.ts

@@ -6,9 +6,10 @@ import { OutboxModule } from './outbox/outbox.module';
 import { ThreadsModule } from './threads/threads.module';
 import { MessageModule } from './messaging/message.module';
 import { HealthController } from './health.controller';
+import { DevController } from './dev/dev.controller';
 
 @Module({
   imports: [PrismaModule, PlatformModule, InteractionsModule, OutboxModule, ThreadsModule, MessageModule],
-  controllers: [HealthController],
+  controllers: [HealthController, DevController],
 })
 export class AppModule {}