feat(iios): retention sweep dev endpoint + /metrics + smoke (P9)

POST /v1/dev/retention/sweep runs the sweep on demand; /metrics gains a global
retention section (snapshot counts by status). smoke-retention.mjs (0-day
windows) proves an aged interaction is redacted in place and surfaces as a
REDACTED snapshot on /metrics.

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

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

@@ -8,6 +8,7 @@ import { AdapterRegistry } from '../adapters/adapter.registry';
 import { PrismaService } from '../prisma/prisma.service';
 import { ActorResolver, type MessagePrincipal } from '../identity/actor.resolver';
 import { SessionVerifier } from '../platform/session.verifier';
+import { RetentionService } from '../retention/retention.service';
 
 /**
  * Dev-only helpers (gated by IIOS_DEV_TOKENS=1). Never enable in production.
@@ -20,6 +21,7 @@ export class DevController {
     private readonly prisma: PrismaService,
     private readonly actors: ActorResolver,
     private readonly session: SessionVerifier,
+    private readonly retention: RetentionService,
   ) {}
 
   @Post('token')
@@ -96,6 +98,13 @@ export class DevController {
     return { eventId: id, scopeId: scope.id };
   }
 
+  /** Run the retention sweep on demand (drives the retention smoke). */
+  @Post('retention/sweep')
+  async retentionSweep() {
+    this.assertDev();
+    return this.retention.sweep();
+  }
+
   private principal(authorization?: string): MessagePrincipal {
     const token = (authorization ?? '').replace(/^Bearer\s+/i, '');
     if (!token) throw new BadRequestException('Authorization bearer token is required');