MJML CLI

The `mjml` package (which provides the `mjml-cli` functionality) is a robust, open-source framework designed to simplify the creation of responsive emails. It allows developers to build emails using a custom XML-like component language (MJML) that is then compiled into production-ready, semantic HTML, ensuring consistent rendering across various email clients. The current stable version, 5.0.1, introduces significant improvements in HTML output, minification, and security. Releases follow a steady cadence, with active development on minor versions and frequent alpha/beta cycles for major upgrades. Key differentiators include its declarative component-based approach, strong focus on email client compatibility, excellent documentation, and vibrant community support, collectively addressing the historical pain points of crafting reliable HTML emails. While the dedicated `mjml-cli` npm package is deprecated, the core `mjml` package provides the command-line interface functionality, enabling compilation, validation, and watch modes directly from the terminal.