Bulk Notification Dispatch System

Problem/Feature Description

A logistics company sends automated notifications to customers at several stages in their delivery workflow: when an order is confirmed, when it ships, and when it arrives. Currently these notifications are sent synchronously inside the HTTP request handler, causing timeouts when email providers are slow and degrading API response times. On busy days, a single slow mail provider call can cascade into request queue buildup.

The team wants to move notification dispatch to a background job system. Each delivery event should add a job to a queue; a separate worker process consumes those jobs and sends the actual notification (email, SMS, etc.). Jobs that fail due to transient provider errors need automatic retries with exponential backoff. The operations team also wants to monitor queue health as part of the standard readiness checks run by Kubernetes.

The solution should be structured as two NestJS modules: one that publishes events when domain actions happen (e.g., order confirmed, order shipped), and one that contains the worker logic. The modules should not be tightly coupled — the publishing module must not directly import the worker module.

Output Specification

Produce TypeScript source files for the NestJS notification queue system. Include:

• Module files for both the publisher side and the worker/processor side
• A service that enqueues jobs (to be called from the domain layer)
• A processor class that handles jobs and sends the notifications
• An event-listener class that reacts to domain events and enqueues jobs
• Health check integration showing readiness probe configuration
• A main.ts snippet or bootstrap file showing application setup

Place files under src/notifications/. Include a IMPLEMENTATION_NOTES.md describing how the modules are wired together, what retry strategy is used, and how queue health is exposed.

Note: You do not need to implement a real email/SMS provider. Use stub implementations (e.g., console.log) for the actual sending logic. Focus on the NestJS architecture and job queue wiring.