site 1.4.1: PLAY/PAUSE key in Open the builder, blinking green like the player's

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

index.html

@@ -8,9 +8,9 @@
   <link rel="preconnect" href="https://fonts.googleapis.com">
   <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
   <link href="https://fonts.googleapis.com/css2?family=Barlow:wght@400;500;600;700&family=Chakra+Petch:wght@600;700&family=JetBrains+Mono:wght@500;700&display=swap" rel="stylesheet">
-  <link rel="stylesheet" href="style.css?v=1.4.0">
-  <script src="assets/versions.js?v=1.4.0"></script>
-  <script src="script.js?v=1.4.0"></script>
+  <link rel="stylesheet" href="style.css?v=1.4.1">
+  <script src="assets/versions.js?v=1.4.1"></script>
+  <script src="script.js?v=1.4.1"></script>
 </head>
 <body>
 
@@ -35,7 +35,7 @@
       <p class="lead">Firmware mods for the Pioneer CDJ-900NXS. We took the player's firmware apart in an emulator and added what newer Pioneer players have: hot cues on the deck, beat jump, colour and 3-band waveforms, keys in Camelot colours and more.</p>
       <p class="lead">Pick the mods you want in the builder. It patches the official 1.31 update in your browser and gives you a normal <code>C900NXS.UPD</code> to install like any update. The boot loader is never touched, so you can always go back to stock.</p>
       <div class="cta">
-        <a class="btn primary" href="builder.html">Open the builder</a>
+        <a class="btn primary play" href="builder.html"><span class="play-key" aria-hidden="true"><svg viewBox="0 0 17 10"><path d="M0 0v10l8-5z"/><rect x="10" y="0" width="2.5" height="10"/><rect x="14.5" y="0" width="2.5" height="10"/></svg></span>Open the builder</a>
         <a class="btn" href="#mods">The mods</a>
         <a class="btn" href="docs.html">Docs</a>
       </div>
@@ -278,7 +278,7 @@
     <div class="wrap">
       <h2 class="section-title">Build it in your browser</h2>
       <p class="section-sub">The <a href="builder.html">builder</a> takes the official 1.31 update and adds the mods you tick, on your computer. Only the main application changes; the boot loader and recovery are copied byte for byte and checked.</p>
-      <div class="cta"><a class="btn primary" href="builder.html">Open the builder</a></div>
+      <div class="cta"><a class="btn primary play" href="builder.html"><span class="play-key" aria-hidden="true"><svg viewBox="0 0 17 10"><path d="M0 0v10l8-5z"/><rect x="10" y="0" width="2.5" height="10"/><rect x="14.5" y="0" width="2.5" height="10"/></svg></span>Open the builder</a></div>
       <p class="section-sub" style="margin-top:28px">Prefer the command line? The Python patcher builds the same file, byte for byte:</p>
       <div class="term"><span class="c"># pick the mods in a list</span>
 <span class="p">$</span> python cdj900nxs_patcher.py C900NXS.UPD