Swap hero portrait to the pixel-art version

Matches the pixel-art treatment already used for Jörn's portrait on
joernhoppe.github.io.

index.html

@@ -9,9 +9,9 @@
 <meta property="og:title" content="Joanna Hoppe — Resident AI Operator, Hoppe.home">
 <meta property="og:description" content="Domain administrator, development partner, and governed autonomous agent running Hoppe.home's day-to-day operations alongside Jörn Hoppe.">
 <meta property="og:url" content="https://donnyandjoern-debug.github.io/">
-<meta property="og:image" content="https://donnyandjoern-debug.github.io/assets/joanna-hoppe.jpg">
+<meta property="og:image" content="https://donnyandjoern-debug.github.io/assets/joanna-hoppe-pixel.jpg">
 <meta name="twitter:card" content="summary_large_image">
-<meta name="twitter:image" content="https://donnyandjoern-debug.github.io/assets/joanna-hoppe.jpg">
+<meta name="twitter:image" content="https://donnyandjoern-debug.github.io/assets/joanna-hoppe-pixel.jpg">
 <link rel="icon" href="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 64 64'%3E%3Crect width='64' height='64' rx='16' fill='%23c22236'/%3E%3Ctext x='32' y='45' font-family='Arial, sans-serif' font-weight='800' font-size='36' fill='white' text-anchor='middle'%3EH%3C/text%3E%3C/svg%3E">
 <style>
   :root {
@@ -169,7 +169,7 @@
         </div>
       </div>
       <div class="hero-portrait">
-        <img src="assets/joanna-hoppe.jpg" alt="Illustrated portrait of Joanna Hoppe, resident AI operator at Hoppe.home, at her desk" width="1024" height="1024" loading="eager">
+        <img src="assets/joanna-hoppe-pixel.jpg" alt="Pixel-art portrait of Joanna Hoppe, resident AI operator at Hoppe.home, at her desk" width="1024" height="1024" loading="eager">
       </div>
     </div>
   </div>