Enable npm's linked install strategy across MDN repositories #1942

Summary

Enable npm's linked install strategy in active MDN repositories that use npm by adding this project-level configuration:

install-strategy=linked

Motivation

The linked strategy installs packages into node_modules/.store and exposes dependencies through links without hoisting them. This prevents packages from accidentally importing undeclared dependencies that happen to be available through the default hoisted layout.

npm now recommends this strategy during package development to catch these "phantom" dependencies before publishing.

npm 11.18.0 graduated the linked strategy from experimental to stable and included the fixes tracked in npm/cli#9608. This is compatible with our current use of Node.js 24 and npm 11.

Proposal

Roll out install-strategy=linked across active MDN repositories that contain an npm lockfile:

1. Require npm 11.18.0 or newer.
2. Add install-strategy=linked to the repository's .npmrc.
3. Run a clean install and the repository's tests.
4. Fix any dependency or tooling issues.
5. Track the resulting pull requests here.

References

• https://github.com/npm/cli/releases/tag/v11.18.0
• https://docs.npmjs.com/using-npm/config/#install-strategy
• [Tracking] install-strategy=linked (isolated mode) bugs npm/cli#9608