Add a notification

A notification is an email template in apps/notifications, queued as a job or asked for through the outbox.

1. Payload. Add a z.object({ template: z.literal("<area>.<name>"), to, data }) to notificationPayload in packages/jobs/src/queues.ts. to is { email, locale }.
2. Copy. Every string in packages/i18n/messages/en.json, under email.<camelCaseName> (compare auth.security-alert: email.securityAlert).
3. Email. A component in packages/email/src/templates/ with its subject, exported from packages/email/src/index.ts, and a preview in packages/email/src/previews/ (bun run --cwd packages/email dev serves them on http://localhost:3030).
4. Template. An entry in templates in apps/notifications/src/dispatch/templates.ts that renders it. The satisfies clause fails check-types until it exists.
5. Trigger. From a service: a producer for notifications-critical and add("send", payload, { jobId }). When it must go out with a change, and never without it: requestNotification(tx, …) (apps/api/src/notifications.ts) in the change's transaction. From a domain event: route the event to events-notifications in eventSubscribers and map it in apps/notifications/src/events/events.processor.ts.
6. Tests. bun run test (i18n completeness, email rendering in packages/email/src/render.test.tsx), then bun run test:integration (apps/notifications/test/notifications.integration.test.ts sends through Mailpit).
7. Finish. The verify skill, then the i18n-checker agent on the new copy and the reviewer agent on the change (delivery through DeliveryLog.claim(), the suppression list).