Rollup Plugin for Application Utilities

The `rollup-plugin-app-utils` package provides a collection of common build utilities designed for Rollup-based projects. Currently stable at version 1.0.6, it does not specify a strict release cadence but appears to be a mature 1.x release. Its core functionalities include an i18n bundler capable of synchronizing translation keys across multiple locale files using a 'back-filling' mechanism, asset copying, dynamic directory preparation and cleanup, and HTML content injection. A key differentiator is its consolidation of these diverse utilities under a single plugin, with the i18n bundler offering intelligent key management. Developers should be aware that several of its file system operations, such as `copyAssets` and `emptyDirectories`, are synchronous, which can impact build performance on very large projects. The plugin is primarily consumed in `rollup.config.js` files, typically within an ESM context.