Fix black-screen render: build with pandoc template

- Convert template.html to a pandoc template ($title$/$body$)
- Update CI deploy and docs to use --template template.html
- Fix header.html title to match canonical
- Ignore generated index.html (regenerated by CI)
- Update AGENTS.md build commands and file structure

template.html

@@ -5,7 +5,7 @@
   <meta charset="utf-8" />
   <meta name="generator" content="pandoc" />
   <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes" />
-  <title>I want to be a dad!</title>
+  <title>$title$</title>
   <link rel="stylesheet" href="styles.css" />
 </head>
 
@@ -13,7 +13,7 @@
   <div class="grid-container">
 
     <div class="header">
-      <h1>I want to be a dad!</h1>
+      <h1>$title$</h1>
     </div>
 
     <div class="menu">
@@ -24,9 +24,7 @@
     </div>
 
     <div class="content">
-      <p>Hello,</p>
-      <p>If you are reading this then I guess you would like to know why.</p>
-      <p>Well thats reserved information. try again next time.</p>
+      $body$
     </div>
 
     <div class="footer">