Fix preview.html to native 320x240 without internal scale.

Card host now scales the iframe; remove broken transform that clipped UI to the corner.

Co-authored-by: Cursor <cursoragent@cursor.com>

firmware/cyd_28r/media/preview.html

@@ -6,12 +6,11 @@
 <title>CLIMATE</title>
 <style>
   *{box-sizing:border-box;margin:0;padding:0}
-  html,body{width:100%;height:100%;overflow:hidden;background:#000}
-  .bezel{width:100%;height:100%;display:grid;place-items:center;background:#1a1408}
+  html,body{width:320px;height:240px;overflow:hidden;background:#000;margin:0}
+  .bezel{width:320px;height:240px;background:#1a1408}
   .screen{
     width:320px;height:240px;background:#0A1018;color:#F2F5FA;
     font:12px/1.2 system-ui,sans-serif;position:relative;overflow:hidden;
-    transform-origin:center;transform:scale(var(--s,1));
   }
   .hdr{display:flex;align-items:center;gap:8px;padding:4px 8px;height:24px}
   .hdr b{font-size:14px;font-weight:700}
@@ -70,10 +69,6 @@
     </svg></div>
   </div>
 </div></div>
-<script>
-(function(){function fit(){var s=document.getElementById('s');var r=s.parentElement.getBoundingClientRect();
-var k=Math.min(r.width/320,r.height/240);s.style.setProperty('--s',k);}
-fit();addEventListener('resize',fit);})();
-</script>
+
 </body>
 </html>