Refactor CORS configuration and add utility, update package.json for dev start command, and create GraphQL query/mutation files

src/graphql/graphql.module.ts

@@ -22,4 +22,4 @@ export class GraphqlModule {
       .apply(GraphQLValidationMiddleware) // Apply the custom middleware
       .forRoutes('graphql'); // Ensure it only applies to the /graphql endpoint
   }
-}
+}