Feed the Home page sections from views instead of hand-placed cards

Problem/Motivation

The Home page placed its country cards and its update cards as Canvas component trees, so the site template shipped a homepage that does not change when the site's content does, and six of its links pointed at stand-in paths that no longer exist.

The "Where We Work" section was also unstyled. The slider's CSS targets its direct > .card-country children, and the view rendered card-overlay instead, so the cards collapsed:

country card box: 11 x 7 px   (then 2 px after a second attempt)

Steps to reproduce

1. Install the Horizon Aid site template.
2. Add or unpublish a country, an event or a blog post.
3. Open the front page: the cards do not follow the content.
4. Follow the "Read more" links in the Our Programs section: they lead to /program-page, which returns 404.

Proposed resolution

• content/canvas_page/01-home.yml — replace the country-slider and impressed-card-slider component trees with block.views_block.countries-latest and block.views_block.blog-latest; set the events section to a single 100 column; repoint five /program-page links at the real /programs/<slug> aliases.
• config/views.view.countries.yml — the latest display renders through components_views_style on vartheme_bs5:country-slider with rows_slot: cards, and its rows use the card view mode.
• config/canvas.content_template.node.country.card.yml — that card view mode renders card-country, so the slider's own CSS sizes it.
• config/canvas.component.sdc.vartheme_bs5_horizonaid.card-country.yml — new. Canvas only generates a component's config once a recipe has finished applying, so the content template above had nothing to bind to until this was exported from a live install.
• recipe.yml — the views.view.blog action gains the same treatment for the Latest Updates slider, followed by setViewsComponentStyleTheme.

Verified as an anonymous visitor at 1440x900 with the cache busted: three views containers on Home (view-id-countries, view-id-events, view-id-blog), country cards measuring 300x420 with a minimum card width of 300px across eleven cards, no broken images, no broken links, no stand-in paths in the markup, and the recipe log reporting Pointed 3 view components in views.view.countries at the vartheme_bs5_horizonaid theme.

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

• The Home page's Where We Work, Events and Latest Updates sections now list real content and follow it as it changes.
• Country cards render at their designed size instead of collapsing.

API changes

• N/A

Data model changes

• A card view mode content template for the Country content type.

Release notes snippet

• The Home page's country, event and update sections are now views-driven, so they follow the site's content, and the Our Programs links point at the real program pages.