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 {}

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

@@ -0,0 +1,29 @@
+import { BadRequestException, Body, Controller, ForbiddenException, Post } from '@nestjs/common';
+import jwt from 'jsonwebtoken';
+
+/**
+ * Dev-only helper: mints an HS256 token a host app would normally sign, so the
+ * browser demo can authenticate. Gated by IIOS_DEV_TOKENS=1 — never enable in
+ * production (the host app signs its own tokens there).
+ */
+@Controller('v1/dev')
+export class DevController {
+  @Post('token')
+  token(@Body() body: { appId: string; userId: string; name?: string; orgId?: string }): { token: string } {
+    if (process.env.IIOS_DEV_TOKENS !== '1') throw new ForbiddenException('dev tokens disabled');
+    let secrets: Record<string, string>;
+    try {
+      secrets = JSON.parse(process.env.APP_SECRETS ?? '{}');
+    } catch {
+      secrets = {};
+    }
+    const secret = secrets[body.appId];
+    if (!secret) throw new BadRequestException(`unknown app: ${body.appId}`);
+    const token = jwt.sign(
+      { sub: body.userId, name: body.name ?? body.userId, appId: body.appId, orgId: body.orgId ?? `org_${body.appId}` },
+      secret,
+      { algorithm: 'HS256', expiresIn: '2h' },
+    );
+    return { token };
+  }
+}

packages/iios-service/src/main.ts

@@ -1,3 +1,4 @@
+import 'dotenv/config';
 import 'reflect-metadata';
 import { NestFactory } from '@nestjs/core';
 import { ValidationPipe } from '@nestjs/common';