fix: add favicon to website

Co-Authored-By: Claude <noreply@anthropic.com>

Author: hyglgithub

docs/index.html

@@ -4,6 +4,7 @@
   <meta charset="UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
   <title>BiViNote - B站视频字幕笔记神器</title>
+  <link rel="icon" type="image/png" href="icons/icon-32.png">
   <style>
     /* 全局重置 */
     * { margin: 0; padding: 0; box-sizing: border-box; }