Introducing Worker Previews: isolated preview environments for every change your agent makes

Introduces Worker Previews, an isolated environment for each Git branch to test changes before production. Each Preview gets its own code, configuration, URL, observability, and state, including isolated Durable Objects and Containers. This enables an Agent Development Lifecycle (ADLC) with atomic, independently deployable, observable, and revisable changes. Previews can be configured with a base configuration and overridden as needed, and Preview URLs can be served on custom domains and protected with Cloudflare Access. This feature aims to improve the reliability and safety of code deployments, especially in agent-assisted development workflows.