Components: Add Modal

Add a reusable Modal component to Prototype using the Modal implementation from Aten JavaScript Components.

The goal is to provide a consistent and accessible modal dialog pattern within Prototype that follows existing component conventions.

Proposed approach

• Create a new Modal component in Prototype.
• Use the Aten modal JavaScript behavior.
• Follow existing Prototype component structure and library patterns.
• Ensure accessibility support (keyboard interaction, focus trapping, ARIA attributes).

Acceptance criteria

• A reusable Modal component exists in Prototype.
• The component integrates the Aten modal behavior.
• Example markup demonstrating trigger, modal container, and close interaction is included.