refactor: use btn class for SearchButton styling

Apply the existing btn class pattern to SearchButton for consistency
with other buttons in the codebase like FullPlayButton.

Co-authored-by: RobbieTheWagner <2640861+RobbieTheWagner@users.noreply.github.com>

Author: Copilot

src/components/SearchButton.tsx

@@ -4,15 +4,17 @@ export default function SearchButton() {
   return (
     <button
       type="button"
-      class="flex items-center gap-2 px-3 py-2 text-sm text-light-text-body dark:text-dark-text-body bg-light-input-bg dark:bg-dark-input-bg rounded-lg border border-light-input-border dark:border-dark-input-border hover:border-light-input-border-focused dark:hover:border-dark-input-border-focused transition-colors"
+      class="btn"
       onClick={() => (isSearchOpen.value = true)}
       aria-label="Search episodes (⌘K)"
     >
-      <span class="search-icon h-4 w-4" aria-hidden="true" />
-      <span class="hidden sm:inline">Search</span>
-      <kbd class="hidden sm:inline-flex items-center gap-1 px-1.5 py-0.5 text-xs bg-light-card dark:bg-dark-card rounded border border-light-input-border dark:border-dark-input-border">
-        <span class="text-xs">⌘</span>K
-      </kbd>
+      <span class="text-light-text-heading flex items-center gap-2 rounded-full px-3 py-2 text-sm dark:text-white">
+        <span class="search-icon h-4 w-4" aria-hidden="true" />
+        <span class="hidden sm:inline">Search</span>
+        <kbd class="hidden sm:inline-flex items-center gap-1 px-1.5 py-0.5 text-xs bg-light-card dark:bg-dark-card rounded border border-light-input-border dark:border-dark-input-border">
+          <span class="text-xs">⌘</span>K
+        </kbd>
+      </span>
     </button>
   );
 }