Built-in durability: Introducing Workflow Development Kit

Introduces the Workflow Development Kit (WDK), an open-source TypeScript framework that makes durability a language-level concept. WDK adds `use workflow` and `use step` directives to async functions, enabling them to pause, persist, and resume across deployments and crashes. It automatically handles queues, retries, and persistence, allowing workflows to pause for extended periods (minutes to months) and resume exactly where they left off. WDK supports pausing with webhooks for external events and is designed to run on any platform via 'Worlds', including a local development environment and Vercel's production environment using Framework-defined infrastructure. The post details the core concepts with code examples for ride-hailing and loyalty reward workflows, and a payment validation workflow using webhooks. It emphasizes that WDK simplifies building reliable systems by abstracting away complex distributed systems infrastructure.