feat(p9): thread purpose + persist consent receipt through OutboundService

Task S2.2: OutboundService.send gains an optional purpose, passes it to the broker,
and persists the returned consentReceiptRef on IiosOutboundCommand (new nullable
column, migration outbound-consent). RouteService.execute passes 'route_forward';
calendar reminders pass 'meeting_reminder'. CMP-DENY → command BLOCKED, no send.
2 tests: receipt recorded on allow, purpose-DENY blocks.

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

packages/iios-service/src/adapters/outbound.service.ts

@@ -27,6 +27,7 @@ export class OutboundService {
     payload: Record<string, unknown>,
     idempotencyKey: string = randomUUID(),
     scopeId?: string,
+    purpose?: string,
   ) {
     const existing = await this.prisma.iiosOutboundCommand.findUnique({ where: { idempotencyKey } });
     if (existing) return existing;
@@ -45,7 +46,7 @@ export class OutboundService {
 
     let result;
     try {
-      result = await this.broker.invoke({ capability: 'channel.send', channelType, target, payload, idempotencyKey, scopeId });
+      result = await this.broker.invoke({ capability: 'channel.send', channelType, target, payload, idempotencyKey, scopeId, purpose });
     } catch (err) {
       // Fail-closed (e.g. PolicyDeniedError): mark the command FAILED, record the attempt, propagate.
       await this.prisma.$transaction([
@@ -56,7 +57,10 @@ export class OutboundService {
     }
 
     const [updated] = await this.prisma.$transaction([
-      this.prisma.iiosOutboundCommand.update({ where: { id: cmd.id }, data: { status: result.outcome, providerRef: result.providerRef } }),
+      this.prisma.iiosOutboundCommand.update({
+        where: { id: cmd.id },
+        data: { status: result.outcome, providerRef: result.providerRef, consentReceiptRef: result.consentReceiptRef },
+      }),
       this.prisma.iiosDeliveryAttempt.create({
         data: { commandId: cmd.id, attemptNo: 1, status: result.outcome, providerRef: result.providerRef, latencyMs: result.latencyMs, errorCode: result.errorCode },
       }),