chore: remove arrow from 'Become a sponsor' link and its CSS rules

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

website/static/style.css

@@ -438,14 +438,6 @@ kbd {
   border-bottom-color: var(--accent);
 }
 
-.sponsor-become-arrow {
-  transition: transform 180ms cubic-bezier(0.22, 1, 0.36, 1);
-}
-
-.sponsor-become:hover .sponsor-become-arrow {
-  transform: translateX(0.3rem);
-}
-
 .sponsor-list {
   list-style: none;
   padding: 0;

website/templates/index.html

@@ -77,7 +77,6 @@
         rel="noopener"
       >
         Become a sponsor
-        <span class="sponsor-become-arrow" aria-hidden="true">&rarr;</span>
       </a>
     </header>
     <ul class="sponsor-list">