Use transparent logo asset in README

assets/islandflow-logo.svg

@@ -1,4 +1,4 @@
-<svg width="1600" height="520" viewBox="0 0 1600 520" fill="none" xmlns="http://www.w3.org/2000/svg" role="img" aria-labelledby="title desc">
+<svg width="1600" height="320" viewBox="0 90 1600 320" fill="none" xmlns="http://www.w3.org/2000/svg" role="img" aria-labelledby="title desc">
   <title id="title">Islandflow logo</title>
   <desc id="desc">Islandflow wordmark with a small palm tree and waterline.</desc>
   <defs>
@@ -27,7 +27,6 @@
       </feMerge>
     </filter>
     <style>
-      .bg { fill: #05070b; }
       .word { font: 700 118px "Menlo", "Consolas", "Liberation Mono", monospace; letter-spacing: 1px; fill: #d2ffc1; }
       .outline { fill: none; stroke: #d2ffc1; stroke-width: 10; stroke-linecap: round; stroke-linejoin: round; }
       .trunk { fill: none; stroke: #f2d39a; stroke-width: 12; stroke-linecap: round; stroke-linejoin: round; }
@@ -35,8 +34,6 @@
     </style>
   </defs>
 
-  <rect class="bg" x="8" y="8" width="1584" height="504" rx="24"/>
-
   <g filter="url(#glowGreen)">
     <text class="word" x="130" y="330">islandflow</text>
   </g>