fix: #3620998 Reshoot the installer card at 500x400 and rewrite the description

Fixes the way Horizon Aid presents itself in the Drupal CMS site-template picker. Closes #3620998.

The card was cropped

The picker renders the card image in a 368x294 box (ratio 1.25) with object-fit: cover and object-position: 50% 0%. The card shipped at 632x304 (ratio 2.08), so the browser discarded roughly 40% of the image width to fill the box: the site logo was cropped off the left edge, the navigation was clipped, and the hero photograph filled the frame with no page around it, so the card read as a photograph rather than a site.

Every other template in the picker ships 500x400, exactly the box ratio, and is therefore never cropped: Haven, Byte, Starter, Everbright, Forma and Mercury Demo all measure 500x400.

screenshot.webp is now 500x400, captured from the home page at a 1500x1200 viewport and scaled down. Measured in the installer afterwards, 0% of it is cropped, and it shows the header and navigation, the complete hero with its heading, sentence and Donate call to action, and the opening of the section below it.

The description did not match the other cards

The other cards open with "Designed for" and say what the template gives you. This one opened with "A site template recipe" and closed on how it was built, which tells a site builder nothing about what they get.

Before:

A site template recipe for NGOs, nonprofits and humanitarian/aid organizations, built the Varbase recipe-first way.

After:

Designed for NGOs, nonprofits and humanitarian aid organizations. Includes country and programme profiles, events, a resource library and a donation page.

It now sits at the same length and register as Byte and Everbright, which render beside it.

Verification

Built a Drupal CMS site from this branch and drove /core/install.php to the site-template step in a real browser, with the card checked both before and after. Screenshots of the shipped card, the new card in context beside its neighbours, and the new card in its selected state are attached to the issue. Nothing else in the recipe changes, and the installed site is unaffected.

AI usage: written with Claude Code (Opus 5) under human review.

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