Does @babel/preset-env preserve ES modules when modules is auto?
Goal: Determine whether @babel/preset-env with modules set to "auto" preserves ES import/export syntax or converts it to CommonJS in a given build pipeline. Constraint: Babel 7.x defaults modules to "auto", which defers the module transform decision to the calling tool. The Babel CLI may resolve auto to CommonJS, while Rollup or webpack configured for ES mod