fix: artists search marks already-followed artists instead of a Follow button

web/src/app/artists/artists-client.tsx

@@ -64,6 +64,8 @@ export function ArtistsClient() {
     refresh();
   }
 
+  const followedMbids = new Set(artists.map((a) => a.mbid));
+
   return (
     <div>
       <form onSubmit={search}>
@@ -77,7 +79,11 @@ export function ArtistsClient() {
             <li key={h.mbid}>
               {h.name}
               {h.disambiguation ? ` (${h.disambiguation})` : ""}{" "}
+              {followedMbids.has(h.mbid) ? (
+                <span> · following</span>
+              ) : (
                 <button onClick={() => follow(h)}>Follow</button>
+              )}
             </li>
           ))}
         </ul>