All workflows that previously ran `npm ci` + a frontend script now install
pnpm via pnpm/action-setup (which honors the `packageManager` field in the
root package.json) and run scripts through `pnpm --filter mas-frontend`.
setup-node gets `cache: "pnpm"` so the pnpm store survives between runs.
The @localazy/cli and semver CLIs used by the release/translation workflows
move from ad-hoc `npm install -g` / `npx --yes` invocations to root
devDependencies, so the version is locked in pnpm-lock.yaml and a single
`pnpm install --frozen-lockfile` makes both available as `pnpm exec`.
misc/build-docs.sh (used by the docs workflow and Cloudflare Pages) is
updated to call `corepack enable` on Cloudflare Pages and to run storybook
through `pnpm --filter mas-frontend exec`.
Quentin Gliech