[4.1] Accessibility: ARIA roles, keyboard focus ring

[underscorekadji]

Milestone: 4 – UX Polish & NFRs
Size: S (≤ 2 hours)
Labels: accessibility

Description

Implement accessibility features including ARIA roles and keyboard navigation to meet WCAG AA standards.

Acceptance Criteria

• ARIA roles implemented (spinbutton, timer)
• WCAG AA contrast requirements met
• Keyboard navigation implemented
• Focus ring styling for keyboard users
• Screen reader compatibility
• Accessibility testing completed

Definition of Done

• PR reviewed & merged
• GitHub Actions pipeline passes (lint → build → smoke)