This issue doesn't seem to be related ot shadcn-ui. I think the npm package @jridgewell/gen-mapping broke something.

First delete your package-lock.json and your node_modules folder. Then install version 0.3.4 of the package and afterwards just do an npm install again.

npm i @jridgewell/[email protected] --force

Should be working then, for me it fixed the problem!