Envify: Environment Variable Replacement

Envify is a Browserify transform that selectively replaces Node.js-style environment variables (e.g., `process.env.NODE_ENV`) with plain string literals during the bundling process. This optimization is crucial for front-end applications, as it allows tools like UglifyJS to perform dead-code elimination, significantly reducing bundle size by stripping out environment-specific code paths (e.g., development-only logging). The package is currently at version 4.1.0 and, while mature and stable, its release cadence is infrequent, reflecting its maintenance status rather than active development. Key differentiators include its tight integration with Browserify's transform pipeline and its ability to purge unused `process.env` references to avoid including Browserify's `process` shim, further optimizing bundle size. It supports both using the system's `process.env` or providing a custom environment object.