Enhance genre removal logic in Album class

Update removeGenre method to check for null IDs.

src/main/java/com/mediamanager/model/Album.java

@@ -74,7 +74,9 @@ public class Album {
 
     public void removeArtist(Artist artist) {
         albumArtists.removeIf(aa ->
-                aa.getArtist() != null && aa.getArtist().getId().equals(artist.getId())
+                aa.getArtist() != null && 
+                aa.getArtist().getId() != null && 
+                aa.getArtist().getId().equals(artist.getId())
         );
     }
 
@@ -96,9 +98,9 @@ public class Album {
     }
 
     public void removeGenre(Genre genre) {
-        albumGenres.removeIf(ag ->
-                ag.getGenre() != null && ag.getGenre().getId().equals(genre.getId())
-        );
+        ag.getGenre() != null && 
+            ag.getGenre().getId() != null && 
+            ag.getGenre().getId().equals(genre.getId())
     }
 
     // Método conveniente para pegar só os gêneros
@@ -219,4 +221,4 @@ public class Album {
                 ", year=" + year +
                 '}';
     }
-}
+}