feat: #3624643 Ship the pages the footer's policy links point at

Issue: https://www.drupal.org/project/rightup/issues/3624643

Three of the footer's seven policy links returned 404 on a fresh install — Advertise, Terms of Use and Accessibility — because no page answered those paths. Privacy Notice never rendered at all: it pointed at the privacy page Drupal CMS ships unpublished, and Drupal hides a link a visitor cannot reach.

Each now has its own published page in the recipe, with the breadcrumb and heading the other pages use. The Privacy Notice menu link points at this recipe's own page, not the Drupal CMS one, whose content this recipe cannot publish.

The bodies are placeholder text that says a site replaces it before launch. No invented legal terms, privacy notice or accessibility statement.

Verified on a fresh Varbase 11 install: /about-us, /contact-us, /advertise, /privacy-notice, /terms-of-use and /accessibility all answer 200, and the footer's automated design check went from 32/34 to 34/34.

AI-Generated: Yes

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