Add favicon to standalone build

src/p4/template.ejs

@@ -6,9 +6,18 @@
     <% const {LONG_NAME, WEBSITE} = require('../packager/brand.js'); %>
     <title><%= LONG_NAME %></title>
     <meta name="description" content="Converts Scratch projects into HTML files, zip archives, or executable programs for Windows, macOS, and Linux.">
-    <% if (!process.env.STANDALONE) { %>
-      <link rel="shortcut icon" href="favicon.ico?v=2" />
-    <% } %>
+    <% if (process.env.STANDALONE) { %>
+      <%
+        const fs = require('fs');
+        const path = require('path');
+        const faviconPath = path.resolve('static/favicon.ico');
+        if (fs.existsSync(faviconPath)) {
+      %>
+        <link rel="shortcut icon" href="data:image/vnd.microsoft.icon;base64,<%= fs.readFileSync('static/favicon.ico').toString('base64') %>">
+      <% } %>
+    <% } else {%>
+      <link rel="shortcut icon" href="favicon.ico?v=2">
+    <% }%>
     <style>
       body[p4-splash-theme="dark"]:not([p4-loaded]) {
         background-color: #111;