feat: Add EthicalAds script and ad placement

Co-authored-by: aider (gpt-5) <aider@aider.chat>

aider/website/_includes/head_custom.html

@@ -32,12 +32,19 @@
   .side-bar { 
     background: linear-gradient(135deg, #ffffff 0%, rgba(20, 176, 20, 0.01) 25%, rgba(20, 176, 20, 0.04) 40%, rgba(220, 230, 255, 0.4) 60%, rgba(205, 218, 255, 0.4) 80%, #F5F6FA 100%);
   }
+
+  /* Ad container spacing */
+  .ea-ad { 
+    margin: 1rem 0; 
+  }
 </style>
 <link rel="alternate" type="application/rss+xml" title="RSS Feed" href="{{ site.url }}/feed.xml">
 <link rel="preconnect" href="https://fonts.gstatic.com">
 <link rel="preload" href="https://fonts.googleapis.com/css?family=Open+Sans:400,700&display=swap" as="style" type="text/css" crossorigin>
 <meta name="viewport" content="width=device-width, initial-scale=1">
 
+<script async src="https://media.ethicalads.io/media/client/ethicalads.min.js"></script>
+
 <!-- Logo Progressive Enhancement for Jekyll pages -->
 <script>
   document.addEventListener('DOMContentLoaded', function() {

aider/website/_includes/nav_footer_custom.html

@@ -1,3 +1,6 @@
+<div class="ea-ad" aria-label="Advertisement">
+  <div data-ea-publisher="aiderchat" data-ea-type="text"></div>
+</div>
 <footer class="site-footer">
     Aider is AI pair programming in your terminal.
     Aider is on