feat: Implement playlist management routes and integrate with music player service

app/models/playlist.py

@@ -276,3 +276,14 @@ class Playlist(db.Model):
             db.session.commit()
 
         return new_playlist
+
+    def save(self, commit: bool = True) -> None:
+        """Save changes to the playlist."""
+        if commit:
+            db.session.commit()
+
+    def delete(self, commit: bool = True) -> None:
+        """Delete the playlist."""
+        db.session.delete(self)
+        if commit:
+            db.session.commit()