fix: The page layouts print the page title in a span, so no page has an h1

Problem/Motivation

No page of the Website Starter site template prints an h1, the front page included: /, /about-us and /blog/getting-started-uikit 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 eleven page layouts of the template place that source straight in their main section. The feature 01-02-01-blog.feature of the template expects one h1 on the front page.

Steps to reproduce

1. Install Drupal with the Website Starter site template 1.0.8 (Display Builder 1.0.0-beta10, UI Suite UIkit 1.0.7).
2. Open /about-us as an anonymous visitor and look for an h1 in the page source.
3. There is none: the title "About us" is printed in a span under the breadcrumb.

Proposed resolution

Put the page title source of the page layouts in the Heading component (ui_suite_uikit:heading), level 1, as Webship Starter did (#3637711), 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

• Every page prints its title as an h1.

API changes

• N/A

Data model changes

• N/A

Release notes snippet

• fix: The page layouts print the page title in a span, so no page has an h1

AI-Generated: Yes