fix: The sign-in page renders no h1 since Display Builder 1.0.0-beta10

Problem/Motivation

The theme's webship-js suite (branch 4.0.x, 74 scenarios in the third shard) fails 02-09-01-display-builder.feature:17: "the page should have exactly one h1" finds 0 on the sign-in page.

The last green run of 4.0.x (2026-11-07) resolved drupal/display_builder 1.0.0-beta9; composer.json floats it as ^1.0@beta, so the pipeline of merge request !17 (an unrelated change to the test suite) resolved 1.0.0-beta10. Its change "Unexpected markup in page title source" (#3621589) no longer wraps the title in the themeable page-title element, so the title slot of the theme's sign-in component (components/sign_in/sign_in.twig) receives plain text and the page has no heading at all.

Every page needs exactly one h1 (WCAG 2.4.6 / 1.3.1); the keyboard and landmark scenarios depend on it too.

Steps to reproduce

1. On a Drupal 11.4 site (PHP 8.4, as in the project's CI), make UIkit Admin 4.0.x-dev the default theme and enable Display Builder 1.0.0-beta10 with its page layout module (display_builder_page_layout).
2. In the theme settings, set "Display Builder page layout" to "Sign-in screens (UIkit Admin)"; it is off by default.
3. Log out and open /user/login.
4. Inspect the page title: there is no h1.

Or run the suite: yarn test on 4.0.x.

Proposed resolution

The sign-in component (and any other page layout or component of the theme that renders the page title slot) wraps the title in <h1> itself instead of relying on Display Builder's page-title markup; keep the heading accessible (one h1 per page, the title text unchanged); confirm with the webship-js suite on 4.0.x.

Related: Webtheme has the same regression and fixes it on its own work item.

Remaining tasks

• ✅ File an issue about this project
• ✅ Addition/Change/Update/Fix to this project
• ✅ Testing to ensure no regression
• ✅ Automated unit/functional testing coverage
• ➖ Developer Documentation support on feature change/addition
• ➖ User Guide Documentation support on feature change/addition
• ➖ UX/UI designer responsibilities
• ✅ Accessibility and Readability
• ❌ Reviewed by a human
• ❌ Code review by maintainers
• ❌ Full testing and approval
• ❌ Credit contributors
• ❌ Review with the product owner
• ✅ Update Release Notes
• ✅ Release

User interface changes

• N/A

API changes

• N/A

Data model changes

• N/A

Release notes snippet

• fix: #3636787 The sign-in page renders no h1 since Display Builder 1.0.0-beta10

AI-Generated: Yes (issue text)