DS Epic: Modal

### **Description**

A Modal is an Isolated & focused view mode for action menus, prompts, and alerts used mostly in Metamask extension products. It presents as a dialog combined with a mask over the underlying (parent) UI, requiring user engagement and dismissal of the modal before allowing interaction with the screen underneath.

The issue describes a Modal concept for MetaMask products but names no files, tests, entry points, or concrete acceptance criteria. Start by locating the existing design-system component structure and clarifying the intended scope, supported behaviors, and definition of done before making changes.

Written by the indexing model from the issue text.