Fix broken client/src/index.ts

[woop]

../client/dist/src/index.js
Module not found: ESM packages (node-fetch) need to be imported. Use 'import' to reference the package instead. https://nextjs.org/docs/messages/import-esm-externals

Import trace for requested module:
./pages/api/playground.ts

https://nextjs.org/docs/messages/module-not-found

On the https://github.com/woop/rebuff/tree/monorepo branch

[woop]

Fixed by @shrumm