Automattic/_s ? reverse-engineered prompt

Build me a clean WordPress starter theme based on this repo, something I can rename and use as the base for a custom site.

I want the theme to feel very minimal out of the box, with a solid default layout, a responsive menu that turns into a simple mobile dropdown, and the usual WordPress templates for posts, pages, archives, search, comments, 404, header, footer, and sidebar. Keep the CSS easy to customize, with the main styles organized so I can quickly change the look without fighting the theme.

Please also make sure it includes the basic theme setup code, the custom header support, the useful template helpers, and the WooCommerce styling and hooks already expected here. If anything needs compiling, just keep the workflow simple and make sure the Sass and JavaScript are wired up properly.

Use the existing starter theme structure, but make it feel polished and ready for me to brand as my own.