feat(mail): tag mail threads source=crm-mail (list separately from chat)

ingest() puts metadata on the interaction, not the thread, and listThreads filters
THREAD metadata — so MailService now tags the thread directly after deposit
(source=crm-mail). Lets the CRM list mail threads apart from Messenger chat
(source=crm-messenger). 7 tests. NOTE: requires an IIOS redeploy.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

packages/iios-service/src/mail/mail.service.spec.ts

@@ -25,7 +25,7 @@ function mail(): MailService {
   const ingest = new IngestService(asService, makeFakePorts(), actors);
   const outbound = new OutboundService(asService, new CapabilityBroker(makeFakePorts(), new CapabilityProviderRegistry()), new IdempotencyService(asService));
   const sender = new TemplatedSender(templates, outbound, makeFakePorts());
-  return new MailService(templates, ingest, sender, actors);
+  return new MailService(templates, ingest, sender, actors, asService);
 }
 const messages = () => new MessageService(asService, makeFakePorts(), actors);
 
@@ -56,6 +56,7 @@ describe('MailService.postInternal', () => {
 
     const thread = await prisma.iiosThread.findUniqueOrThrow({ where: { id: res.threadId } });
     expect(thread.subject).toBe('Welcome Dana');
+    expect((thread.metadata as { source?: string } | null)?.source).toBe('crm-mail'); // lists separately from chat
 
     // The load-bearing assertion: the RECIPIENT can see the thread in their inbox.
     const bobThreads = await messages().listThreads(bob);