Title: Add make:dto Artisan generator

Summary

Adds a new Artisan generator command php artisan make:dto {Name} which scaffolds a basic DTO class under App\DTOs.
This is intended as a small convenience helper for projects that use DTO objects.

Changes

• New Console Command: App\Console\Commands\MakeDtoCommand
• New default stub: stubs/dto.stub
• Default namespace: App\DTOs
• Tests: tests/Feature/MakeDtoCommandTest.php (verifies file creation and DTO behavior)

How to test

1. composer install
2. ./vendor/bin/pint
3. php artisan make:dto SampleData
4. ./vendor/bin/phpunit --filter MakeDtoCommandTest

Notes

• No breaking changes expected.
• If maintainers prefer this to live as a community package rather than in framework core, I'm happy to extract it — please advise.
• cc @taylorotwell (modest ping — please feel free to reassign to maintainers if more appropriate)

Closes: # (if any)