sendWelcomeEmailJob takes IMailerService, validates the typed input
(userId + email), and delegates to mailer.sendWelcome. The
onAuthUserSignedUpHandler now takes IJobQueue and enqueues
"marketing-pages.send-welcome-email" with the event payload.
Both binders bind a RecordingMailerService at the IMailerService
symbol (production placeholder until a real adapter ships) and pass
mailer / queue into the wrapped factories. Dev-seed additionally
queue.register()s the slug so the in-memory queue dispatches via
the wrapped job; production relies on the generated Payload event-task
to resolve the wrapped handler from the container.
Danijel Martinek
7e844c646d