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 #4132

Part one of #3850, which stalled or went red as one change. This part changes only the markup; the stylesheet and docs/DESIGN.md are part two.

Done:

• [ ] The front page's app tiles are drawn with §5's card and the look image from src/web/ui.ts and §5's classes. None of .app-tile .app-tile-body .app-tile-desc .app-tile-look .app-tile-name appears in the page's HTML.
• [ ] Do not delete the rules from src/web/style/content.ts and do not edit docs/DESIGN.md. Part two does that, and the design check stays green because the classes are still defined and named.
• [ ] Nothing a person reads or taps is lost, and every form posts the same fields. A test asserts the old names are absent and the words, links and forms are present.

Files: src/web/studio/home.ts, a test. Touch only the tiles' markup; other issues and pull #4117 edit home.ts, so rebase onto whatever lands first. Before pushing, run bun x tsc --noEmit, bun test test/design-lint.test.ts and the page's tests. No screenshots: the sandbox has no browser.