[Feature request] Add a Mobile variant to the Checkpoints component

[janmaarten-a11y]

Description

The toolkit currently includes a checklist component for verifying accessibility considerations, but it is oriented toward desktop experiences. Mobile interfaces have their own set of accessibility concerns, such as touch target sizing, gesture alternatives, screen reader rotor navigation, and orientation support.

Requested change

Add a mobile-specific variant of the checklist component that covers accessibility considerations unique to the mobile context. This could include items such as:

• Each screen having a maximum of one title
• Every touch interaction can be also accessed with a keyboard
• Focus order is annotated and matches the intention of the design. Avoid focus that jumps back and forth across the screen to reach items visually out of order.
• Touch target minimum sizes (per WCAG 2.2 Success Criterion 2.5.8 Target Size)
• Availability of gesture alternatives for complex interactions
• Support for both portrait and landscape orientations
• Screen reader compatibility for mobile-specific UI patterns (e.g., bottom sheets, swipe actions)
• Support for platform accessibility features like Dynamic Type / text scaling

Why

Mobile annotation is an increasingly common need as teams design responsive and native mobile experiences. Having a dedicated mobile checklist helps designers verify that accessibility requirements specific to smaller screens and touch interactions are accounted for during the design phase, rather than discovered later in development or testing.