The front page's app tiles draw §5's card and the look image, and .app-tile, .app-tile-body, .app-tile-desc, .app-tile-look, .app-tile-name leave the markup #4175

The front page's app tiles now use §5's card() and the .look picture, and none of the five app-tile* class names appear in the page's HTML. bun test test/front.test.ts test/design-lint.test.ts passes (24 tests). bun x tsc --noEmit reports only the sandbox's missing bun type definitions, none from home.ts or the test. I did not run the rest of the page's tests.

• Markup: tile() in src/web/studio/home.ts now builds the tile with card(..., {pad:false}). Inside is an <a class="look"> wrapping the same <img> with its width and height. Below it, a .card-body.stack.stack-tight holds the repository name as a link, the description (or owner) as muted small truncate with the same title, and the state badge. The tile has no forms.
• Link change: the whole tile used to be one link. Now the picture and the name both link to the repository, and the picture link is tabindex="-1" aria-hidden="true" so keyboard and screen-reader users get only the name link. The description and badge no longer link.
• Test: an extra assertion in the existing ranked-shelf test in test/front.test.ts checks that the five old names are absent. It also checks that the shelf has .card, the picture link, the name link and the "the one app" words.
• Left alone: src/web/style/content.ts and docs/DESIGN.md are untouched, so the old rules stay for part two to remove. Until then the tiles use the generic .card styling instead of the old border and hover accent.
• Look has no thumb slot: ui.ts has no look helper, so I wrote the .look markup directly. I left off data-slot because the thumb slot is a 30×40 box, too small for a tile.

Closes #4132

The front page's app tiles now use §5's card() and the .look picture, and none of the five app-tile* class names appear in the page's HTML. bun test test/front.test.ts test/design-lint.test.ts passes (24 tests). bun x tsc --noEmit reports only the sandbox's missing bun type definitions, none from home.ts or the test. I did not run the rest of the page's tests.

• Markup: tile() in src/web/studio/home.ts now builds the tile with card(..., {pad:false}). Inside is an <a class="look"> wrapping the same <img> with its width and height. Below it, a .card-body.stack.stack-tight holds the repository name as a link, the description (or owner) as muted small truncate with the same title, and the state badge. The tile has no forms.
• Link change: the whole tile used to be one link. Now the picture and the name both link to the repository, and the picture link is tabindex="-1" aria-hidden="true" so keyboard and screen-reader users get only the name link. The description and badge no longer link.
• Test: an extra assertion in the existing ranked-shelf test in test/front.test.ts checks that the five old names are absent. It also checks that the shelf has .card, the picture link, the name link and the "the one app" words.
• Left alone: src/web/style/content.ts and docs/DESIGN.md are untouched, so the old rules stay for part two to remove. Until then the tiles use the generic .card styling instead of the old border and hover accent.
• Look has no thumb slot: ui.ts has no look helper, so I wrote the .look markup directly. I left off data-slot because the thumb slot is a 30×40 box, too small for a tile.