fix(fediverse): set default castopod avatar url when actor avatar is not present

app/Config/Fediverse.php

@@ -23,6 +23,10 @@ class Fediverse extends FediverseBaseConfig
      */
     public string $noteObject = NoteObject::class;
 
+    public string $defaultAvatarImagePath = 'media/castopod-avatar_thumbnail.webp';
+
+    public string $defaultAvatarImageMimetype = 'image/webp';
+
     public function __construct()
     {
         parent::__construct();

app/Entities/Actor.php

@@ -48,7 +48,7 @@ class Actor extends FediverseActor
             return $this->podcast->cover->thumbnail_url;
         }
 
-        return $this->attributes['avatar_image_url'];
+        return parent::getAvatarImageUrl();
     }
 
     public function getAvatarImageMimetype(): string
@@ -57,6 +57,6 @@ class Actor extends FediverseActor
             return $this->podcast->cover->thumbnail_mimetype;
         }
 
-        return $this->attributes['avatar_image_mimetype'];
+        return parent::getAvatarImageMimetype();
     }
 }