v0.4.0 — ticket attachments (ADR-002) Aditive feature: tabla ticket_attachments, model TicketAttachment, enum AttachmentUploaderRole, AttachmentService, event AttachmentUploaded, TicketAuthorizationContract extendido con 3 métodos, BasicTicketAuthorization con defaults permissive, Ticket::attachments() relation, config attachments.* con defaults restrictivos. Consumers deben correr 'php artisan migrate' tras composer update. 51 Pest tests pasando (+10 nuevos). PHPStan max clean. Pint clean. Ver CHANGELOG.md y docs/ADR-002-ticket-attachments.md.