Build command fails on generated theme

Problem/Motivation

npm run build fails in custom generated theme.

Steps to reproduce

1. Generate a custom theme according to the instructions in README.md
2. Navigate to the new theme.
3. Run nvm use
4. Run npm run build

The result is

npm error code E404
npm error 404 Not Found - GET https://registry.npmjs.org/string.prot.trimstart - Not found
npm error 404
npm error 404  'string.custom_theme.trimstart@1.0.8' is not in this registry.
npm error 404
npm error 404 Note that you can also install from a
npm error 404 tarball, folder, http url, or git url.
npm error A complete log of this run can be found in: /home/john/.npm/_logs/2025-06-08T06_59_03_198Z-debug-0.log

Proposed resolution

Remove package-lock.json from the distribution.