task: #3635749 Update Node.js to >= 24.0 and move Vardoc 4.0.x to Drupal 11.4

Moves the Node.js pins on 4.0.x to 24, the floor Drupal core main declares in core/package.json. Node.js 20 reached end of life on 30 April 2026.

Issue: https://www.drupal.org/i/3635749

• engines: node >= 24.0 in package.json and themes/vardoc_theme/package.json.
• Keep Yarn Classic: Yarn 4 cannot install the farbtastic tarball.
• Remove yarn.lock and ignore JavaScript lockfiles.
• Caret dependency ranges, as Drupal core does.

Checked in node:24 (v24.22.2) with no lockfile present: the Yarn Classic 1.22.22 install passes. Vardoc runs no GitLab CI, so there is no pipeline.

Remaining tasks

• Replace the farbtastic GitHub tarball, which has no package.json, so Yarn 4 cannot install it
• themes/vardoc_theme uses gulp-sass 4, which pulls in node-sass 4.14.1; its npm install already fails on Node 22
• yarn lint:js reports 423 problems, the same 423 as the base branch on Node 22; no CI runs it

AI-Generated: Yes

Drupal 11.4 (added on request)

• Vardoc 4.0.x now requires drupal/core ~11.4.0, and core_version_requirement: ~11.4.0 on the profile, its modules and its theme. Drupal 10 is no longer supported on this branch.
• Varbase modules, vartheme_bs4 and vardot/varbase-patches move to ~9.2.0 (the Varbase line for Drupal ~11.4); varbase_layout_builder ~10.0.0, varbase_workflow ~2.2.0, vartheme_claro ~3.1.0, as in the Varbase 9.2.x profile.
• Contrib for Drupal 11: fontawesome ~2 → ~3, book_tree_menu ~2 → ~3. vardot/varbase-patches is now in allow-plugins.
• Voting API removed: drupal/votingapi, drupal/votingapi_widgets and npm-asset/jquery-bar-rating, with the book rating field (field_rating), its permissions and displays in the Vardoc Book recipe, and the vote entities and ratings in the Vardoc Demo content.
• CI builds on Drupal 11.4.11. MR pipeline 1035224 is green; the lint jobs are advisory on this branch.

Remaining tasks

• Install the profile on Drupal 11.4 and check the book pages, Font Awesome icons and the book tree menu after the major upgrades (CI builds the codebase but does not install the profile).

Checkpoints:

• 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