fix(home): floor frame-card preview to 50dvh so landscape frames feel hero-sized

The natural 5:3 aspect ratio renders landscape devices as a ~200px-tall strip
on a phone — too small now that the carousel gives each slide the full
viewport. Set min-height: 50dvh so landscape preview is at least half the
screen tall, with object-fit: contain letterboxing the photo. Portrait
frames (3:5) still drive their height from the natural aspect ratio, since
that's already taller than the 50dvh floor.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

public/build/index.html

@@ -14,7 +14,7 @@
     <meta name="mobile-web-app-capable" content="yes" />
     <meta name="apple-mobile-web-app-status-bar-style" content="default" />
     <meta name="apple-mobile-web-app-title" content="pictureFrame" />
-    <script type="module" crossorigin src="/build/assets/index-CtkfMKf5.js"></script>
+    <script type="module" crossorigin src="/build/assets/index-BxH1sIci.js"></script>
     <link rel="modulepreload" crossorigin href="/build/assets/_plugin-vue_export-helper-DVo1OUMD.js">
     <link rel="stylesheet" crossorigin href="/build/assets/index-BlLBHR1q.css">
   </head>