Building a Multi-Channel Notification Service in .NET 8

TL;DR — This post walks through building a complete notification service in .NET 8 that delivers messages across Email, SMS, and Push channels using a message queue, Scriban template engine, per-channel rate limiting, and parallel fan-out dispatch. Full source code on GitHub at the end. Why Build a Notification Service? Every production application eventually needs to notify its users — a welcome email, a password reset SMS, a push alert when their order ships. The naive approach is to call Send