Add HTML on-device UI preview for flasher catalog.

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

firmware/cyd_28r/media/preview.html

@@ -0,0 +1,61 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+<meta charset="utf-8" />
+<title>AIR</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}
+  .screen{width:320px;height:240px;background:#0A1018;color:#F2F5FA;font:12px/1.2 system-ui,sans-serif;
+    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}.up{color:#7E90A8}.sp{margin-left:auto;display:flex;gap:6px;align-items:center;color:#7E90A8}
+  .led{width:9px;height:9px;border-radius:50%;background:#4CAF7A}
+  .row{display:flex;gap:6px;padding:0 8px}
+  .panel{flex:1;height:118px;background:#121C2A;border:1px solid #1E2C40;border-radius:6px;padding:6px 8px;position:relative}
+  .cap{color:#7E90A8;font-size:11px}
+  .gauge{width:90px;height:90px;margin:4px auto 0;border-radius:50%;
+    background:conic-gradient(#4DA3FF 0 40%, #243247 0);
+    mask:radial-gradient(farthest-side,transparent 62%,#000 63%);
+    -webkit-mask:radial-gradient(farthest-side,transparent 62%,#000 63%)}
+  .panel.tvoc .gauge{background:conic-gradient(#B07CFF 0 28%, #243247 0)}
+  .val{position:absolute;left:0;right:0;top:44px;text-align:center;font-size:20px;font-weight:700;color:#4DA3FF}
+  .panel.tvoc .val{color:#B07CFF}
+  .unit{font-size:10px;color:#7E90A8}
+  .rng{position:absolute;left:0;right:0;bottom:6px;text-align:center;color:#7E90A8;font-size:11px}
+  .bot{margin:6px 8px 0;height:78px;background:#121C2A;border:1px solid #1E2C40;border-radius:6px;display:flex;gap:8px;padding:8px}
+  .info{width:96px}.ok{color:#4CAF7A;font-size:14px;font-weight:700}
+  .meta{margin-top:10px;color:#7E90A8;font-size:11px}
+  .chart{flex:1;background:#0E1622;border-radius:4px}
+  .chart svg{width:100%;height:100%}
+</style>
+</head>
+<body>
+<div class="bezel"><div class="screen" id="s">
+  <div class="hdr"><b>AIR</b><span class="up">up 03:10</span>
+    <span class="sp"><span>GOOD</span><span class="led"></span></span></div>
+  <div class="row">
+    <div class="panel"><div class="cap">eCO2</div><div class="gauge"></div>
+      <div class="val">612<span class="unit"> ppm</span></div><div class="rng">baseline</div></div>
+    <div class="panel tvoc"><div class="cap">TVOC</div><div class="gauge"></div>
+      <div class="val">84<span class="unit"> ppb</span></div><div class="rng">SGP30</div></div>
+  </div>
+  <div class="bot">
+    <div class="info"><div class="ok">FRESH</div>
+      <div class="meta">SDA22 · SCL27<br/>IAQ index OK</div></div>
+    <div class="chart"><svg viewBox="0 0 180 60" preserveAspectRatio="none">
+      <polyline fill="none" stroke="#4DA3FF" stroke-width="2"
+        points="0,35 30,32 60,30 90,28 120,33 150,29 180,27"/>
+      <polyline fill="none" stroke="#B07CFF" stroke-width="2"
+        points="0,48 30,46 60,44 90,45 120,42 150,43 180,41"/>
+    </svg></div>
+  </div>
+</div></div>
+<script>
+(function(){function fit(){var s=document.getElementById('s');var r=s.parentElement.getBoundingClientRect();
+s.style.setProperty('--s',Math.min(r.width/320,r.height/240));}
+fit();addEventListener('resize',fit);})();
+</script>
+</body>
+</html>

firmware/cyd_28r/meta.json

@@ -0,0 +1,10 @@
+{
+  "boardId": "esp32-2432s028",
+  "name": "CYD SGP30 air quality dashboard",
+  "summary": "eCO2 and TVOC air-quality gauges",
+  "description": "SGP30 on SDA=GPIO22 / SCL=GPIO27. Dual arcs and IAQ status.",
+  "tags": ["air", "sgp30", "eco2", "tvoc"],
+  "media": {
+    "preview": "media/preview.html"
+  }
+}