Use a separate folder for the TypeScript build for Node.js in the dist
folder. This makes each type of build consistently have its own output
folder instead of being interleaved with the Node.js build.
Change the expected exported name of plugin declarations to be "plugin"
at the main entrypoint instead of the default export. This makes the
plugin's code organisation more flexible especially when using CommonJS
JavaScript modules as they can export additional symbols from the
plugin declaration file.
Cooldude2606