freesewing/pattern ? reverse-engineered prompt

Build me a simple FreeSewing pattern starter from this template repo.

I want the project to run cleanly in development, with the pattern code in place, a working example app, and the usual setup so I can open it in the browser and see the pattern preview. Please make sure the template feels like a real starting point for a new sewing pattern, with sensible default files, a basic pattern definition, and clear example measurements so I can test that everything is wired up correctly.

If anything is missing or outdated, fix it so a new user can clone the repo, install the dependencies, start the main app and the example app, and immediately begin editing their own pattern. If you need current FreeSewing docs or best practices, look them up online and follow the standard approach. Keep it polished, minimal, and ready for someone to fork into their own custom pattern project.