fix: The default page layout prints the page title in a span, so a node page has no h1

Problem/Motivation

A node page of the Webship Starter site template prints no <h1>: /support, /docs, /products/marigold, /contact and the 404 page fail the webship-js step "the page should have exactly one h1" with "Expected 1 <h1>, found 0." Display Builder 1.0.0-beta10 prints the page title source as the title text only, in a <span> (#3621589), and the default page layout of the template places that source straight in its main section. The front page and the sign-in page have an h1: their layouts do not use the bare source.

Steps to reproduce

1. Install Drupal with the Webship Starter site template 1.0.8 (Display Builder 1.0.0-beta10, UI Suite UIkit 1.0.7).
2. Run curl -s https://<site>/support | grep -c '<h1'.
3. The count is 0: the title is printed as <span>Support</span> under the breadcrumb.

Proposed resolution

Put the page title source of the default page layout in the Heading component (ui_suite_uikit:heading), level 1, as webtheme (#3564799) and UIkit Admin (#3636787) did, and conflict with the Display Builder releases before 1.0.0-beta10, which print an h1 of their own.

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

• A node page prints its title as an h1.

API changes

• N/A

Data model changes

• N/A

Release notes snippet

• fix: The default page layout prints the page title in a span, so a node page has no h1

AI-Generated: Yes