feat(独立应用): OFDGo WebUI支持安装为独立应用，统一图标与窗口配色

assets/webui/index.html

@@ -3,7 +3,10 @@
 <head>
 	<meta charset="utf-8">
 	<meta name="viewport" content="width=device-width, initial-scale=1">
+	<meta name="theme-color" content="#fbfcfd">
 	<title>OFDGo WebUI</title>
+	<link rel="manifest" href="./ofdgo.json">
+	<link rel="icon" type="image/svg+xml" href="./ofdgo.svg">
 	<link rel="stylesheet" href="./ofdgo.css">
 </head>
 <body>