feat: wire up BLBLogo and FBBanner as site icon and OG image

- favicon.ico, icon-192/512, apple-touch-icon → BLBLogo.png
- og:image + twitter:card image → FBBanner.png (OG image)
- Display BLBLogo in About section (replaces skull placeholder)
- Add Next/Image import and aboutLogo CSS class

pages/index.tsx

@@ -1,4 +1,5 @@
 import Head from "next/head";
+import Image from "next/image";
 import styles from "@/styles/Home.module.css";
 
 export default function Home() {
@@ -93,7 +94,14 @@ export default function Home() {
             </p>
           </div>
           <div className={styles.aboutVisual}>
-            <span className={styles.aboutPlaceholder}>💀</span>
+            <Image
+              src="/blb-logo.png"
+              alt="Bone Lord Bob"
+              width={400}
+              height={600}
+              className={styles.aboutLogo}
+              priority
+            />
           </div>
         </section>