feat: integrate icon

frontend/index.html

@@ -3,12 +3,13 @@
   <head>
     <meta charset="UTF-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1" />
+    <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
     <title>Plotzilla</title>
   </head>
   <body>
     <header class="topbar" id="topbar">
       <div class="win-controls" id="win-left"></div>
-      <div class="brand"><span class="logo" data-icon="logo"></span>Plotzilla</div>
+      <div class="brand"><img class="logo" src="/favicon.svg" alt="" />Plotzilla</div>
       <div class="doc">
         <span id="doc-name" class="doc-name">Untitled</span>
         <span id="save-state" class="save-state"></span>