feat(playlist): 优化歌单页面展示逻辑

- 移除歌单首歌曲数量的冗余展示
- 增加歌单总歌曲数量的展示
- 更新歌单列表和歌单详情页面的样式
- 在后端增加@EntityGraph注解，优化数据查询性能

music-houduan/src/main/java/com/test/musichouduan/repository/PlaylistRepository.java

@@ -7,6 +7,8 @@ import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
+import org.springframework.data.jpa.domain.Specification;
+import org.springframework.data.jpa.repository.EntityGraph;
 import org.springframework.data.jpa.repository.Query;
 import org.springframework.stereotype.Repository;
 
@@ -18,6 +20,9 @@ import java.util.List;
 @Repository
 public interface PlaylistRepository extends JpaRepository<Playlist, Long>, JpaSpecificationExecutor<Playlist> {
 
+    @EntityGraph(attributePaths = {"musics", "creator", "type"})
+    Page<Playlist> findAll(Specification<Playlist> spec, Pageable pageable);
+
     @Query("SELECT pt.name, COUNT(p) FROM Playlist p JOIN p.type pt GROUP BY pt.name")
     List<Object[]> countByPlaylistType();