feat(前端界面): 优化未打开文件时的默认标题

assets/webui/index.html

@@ -4,7 +4,7 @@
 	<meta charset="utf-8">
 	<meta name="viewport" content="width=device-width, initial-scale=1">
 	<meta name="theme-color" content="#fbfcfd">
-	<title>OFDGo WebUI</title>
+	<title>OFDGo WebUI - 纯粹的OFD阅读器，完全本地、离线可用</title>
 	<link rel="manifest" href="./ofdgo.json">
 	<link rel="icon" type="image/svg+xml" href="./ofdgo.svg">
 	<link rel="stylesheet" href="./ofdgo.css">