refactor: improve error handling in user service and ensure consistent error throwing

Author: tomast1337

apps/backend/src/song/song-webhook/song-webhook.service.ts

@@ -48,7 +48,7 @@ export class SongWebhookService implements OnModuleInit {
         body: JSON.stringify(webhookData),
       });
 
-      const data = await response.json();
+      const data = (await response.json()) as { id: string };
 
       //this.logger.log(`Posted webhook message for song ${song.publicId}`);
       return data.id; // Discord message ID

apps/backend/src/user/user.service.ts

@@ -32,7 +32,11 @@ export class UserService {
         new: true, // return the updated document
       })) as UserDocument;
     } catch (error) {
-      throw new Error(error);
+      if (error instanceof Error) {
+        throw error;
+      }
+
+      throw new Error(String(error));
     }
   }