Update Node.js to >= 24.0 and Yarn to 4.18.1 for Vartheme Claro

Problem/Motivation

Node.js 20 reached end of life on 30 April 2026, and Drupal core main now requires "node": ">= 24.0" in core/package.json. Vartheme Claro still declares Node 18 and Node 20 in its engines, and Node 20 in GitLab CI.

Node 24 is the LTS line, latest v24.22.2, and it is one of the lines the November 2026 security releases will patch. Pinning the major picks those patches up with no further change. Local systems should use Node.js 24 or 26.

Steps to reproduce

1. On 4.0.x and 3.0.x, open package.json: the engines say "node": ">= 18.0" and "yarn": ">= 1.6", with a Yarn 1 yarn.lock.
2. On 3.1.x, the engines say "node": ">= 20.0", packageManager is yarn@4.9.3, and .gitlab-ci.yml installs NodeSource setup_20.x.

Proposed resolution

• package.json engines: "node": ">= 24.0". on all three branches.
• 4.0.x (Yarn Classic) and 3.1.x (Yarn 4.9.3): Yarn moves to yarn@4.18.1 with the floor ">= 4.18.1", and .yarnrc.yml follows the Varbase standard (approvedGitRepositories, enableScripts, nodeLinker: node-modules, npmMinimalAgeGate: 0), which Yarn before 4.14.0 rejects.
• 3.0.x stays on Yarn Classic: Yarn 4 cannot resolve the farbtastic GitHub tarball, which has no package.json.
• .gitlab-ci.yml on 3.1.x: NodeSource setup_24.x.
• .gitlab-ci.yml: the composer and stylelint jobs set YARN_RC_FILENAME: .yarnrc.core.yml and YARN_NODE_LINKER: node-modules, so Drupal core's own Yarn 4.9.1 in those jobs does not read the project .yarnrc.yml, whose keys need Yarn 4.14.
• yarn.lock is removed on all three branches and .gitignore now ignores yarn.lock, package-lock.json and pnpm-lock.yaml, so installs resolve from package.json. CI on 3.1.x already sets YARN_ENABLE_IMMUTABLE_INSTALLS to "false".
• Dependency ranges in package.json use carets, the way Drupal core writes them: exact versions, ~ and .x ranges become ^MAJOR.MINOR.PATCH, with no major bump.

AI-Generated: Yes

Remaining tasks

• ✅ File an issue
• ✅ Addition/Change/Update/Fix
• ❌ Testing to ensure no regression
• ❌ Move 3.0.x to Yarn 4 once the farbtastic and joyride GitHub tarballs are replaced
• ➖ Automated unit testing coverage
• ➖ Automated functional testing coverage
• ➖ UX/UI designer responsibilities
• ➖ Readability
• ➖ Accessibility
• ➖ Performance
• ➖ Security
• ➖ Developer Documentation
• ➖ User Guide Documentation
• ❌ Reviewed by human
• ❌ Code review by maintainers
• ❌ Full testing and approval
• ❌ Credit contributors
• ❌ Review with the product owner
• ❌ Release notes snippet
• ✅ Release

User interface changes

• N/A

API changes

• N/A

Data model changes

• N/A

Release notes snippet

• Node.js 24 or newer is now required, in the engines and CI. Yarn 4.18.1 is the package manager.