Apply lock state to category-tile cover previews too

Verified the whole reward-lock feature against a real library with an
actual browser (Playwright + headless Chromium): the album-grid cards
already showed the question-mark placeholder for a locked album, but
its 2x2 preview thumbnail in the category-tile view (the screen before
drilling into an artist/category) still rendered the real cover art,
since that Cover call never received the locked prop.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web/src/components/BrowseView.tsx

@@ -728,6 +728,7 @@ function CategoryTile({
               fit="height"
               radius="4px"
               label={shown.length === 1}
+              locked={album.locked}
             />
           </div>
         ))}