npm run dev now runs scripts/dev-env.ts first, which creates .dev/site.env with
a known dev password and a random session secret, so a fresh clone serves a
working admin without anyone hand-building a hash. Adds .vscode launch
configurations and tasks for the dev server, one test file, and check-site, and
brings scripts/ under typecheck, which it had been missing.
The store keeps a Menu Set's state in the directory layout (drafts/ versus
published/) and its metadata in a manifest, with publishing as a single
directory rename. Editing is allowed on Drafts only, so a published menu can
never change under a customer. Stages 2 and 3 of docs/plan.md, with tests.