Add Google AdSense meta tag to site pages (#282)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>

Author: Copilot

site/demo.html

@@ -8,6 +8,7 @@
 	<meta name="keywords" content="timeago, timeago.js, datetime, time ago, javascript timeago, react-timeago, jquery-timeago" />
 	<meta name="description" content="timeago.js is a tiny library (less than 2kb) used to format date with '*** time ago' statements. eg: '3 hours ago'. No dependencies. Supports automatically updating fuzzy timestamps." />
 	<link rel="canonical" href="https://timeago.ling.pub/demo.html" />
+	<meta name="google-adsense-account" content="ca-pub-7292810486004926" />
 	<link rel="shortcut icon" href="clock.png" />
 	<link rel="bookmark" href="clock.png" />
 	<link rel="stylesheet" type="text/css" href="css.css" />

site/index.html

@@ -23,6 +23,7 @@
     <meta name="twitter:description" content="timeago.js is a tiny library (less than 2kb) used to format datetime with '*** time ago' statements. No dependencies. Supports i18n and automatic updates." />
     <meta name="twitter:image" content="https://timeago.ling.pub/clock.png" />
 
+    <meta name="google-adsense-account" content="ca-pub-7292810486004926" />
     <link rel="shortcut icon" href="./clock.png" />
     <link rel="bookmark" href="./clock.png" />
     <link rel="stylesheet" type="text/css" href="./css.css" />