fix: Update Gumroad URL to correct account

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: silversurfer562

website/app/book/page.tsx

@@ -1,7 +1,7 @@
 import Link from 'next/link';
 
 // Gumroad product URL for pay-what-you-want book
-const GUMROAD_BOOK_URL = 'https://smartaimemory.gumroad.com/l/empathy-book';
+const GUMROAD_BOOK_URL = 'https://roebucksmith.gumroad.com/l/empathy-book';
 
 export default function BookPage() {
   return (