Update Node.js to >= 24.0 and Yarn to 4.18.1 for AI Figma

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. AI Figma still declares "node": ">= 22.0" and "yarn": ">= 1.6", and its GitLab CI runs Node 22.

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 1.0.x, open package.json: the engines say "node": ">= 22.0" and "yarn": ">= 1.6", while packageManager is yarn@4.9.3.
2. Open .gitlab-ci.yml: the functional test jobs install NodeSource setup_22.x and then run yarn install through corepack.

Proposed resolution

• package.json engines: "node": ">= 24.0". 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.
• .gitlab-ci.yml: NodeSource setup_24.x for the functional test jobs. YARN_ENABLE_IMMUTABLE_INSTALLS is "false", since no lockfile is committed.
• .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 and .gitignore now ignores yarn.lock, package-lock.json and pnpm-lock.yaml, and .yarn/ too, so installs resolve from package.json. This undoes the lockfile part of #3625890.
• 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
• ➖ 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.