feat(#184): enhance accessibility and testing in frontend

[0xVida]

Summary

This PR improves the frontend's accessibility by introducing automated accessibility testing, enforcing accessibility best practices through linting, and updating interactive components to provide a more inclusive experience for keyboard and screen reader users.

Changes

• Integrated jest-axe and @axe-core/react for automated accessibility testing.
• Added and configured eslint-plugin-jsx-a11y to enforce accessibility best practices during development.
• Added accessibility assertions to component tests.
• Configured Lighthouse CI accessibility audits.
• Added accessible labels (aria-label/aria-labelledby) to interactive elements where required.
• Improved keyboard accessibility with visible focus-visible styles.
• Audited and updated color contrast to meet WCAG AA requirements.

Acceptance Criteria

• jest-axe is integrated into component tests and runs automated accessibility assertions.
• eslint-plugin-jsx-a11y is configured and all violations are fixed.
• Lighthouse CI runs accessibility audits with a minimum score of 90.
• All interactive elements have accessible names (aria-label, aria-labelledby).
• Color contrast ratios meet WCAG AA minimum requirements (4.5:1 for normal text, 3:1 for large text).
• Keyboard tab order is logical and visible with focus-visible styles.

Verification

• jest-axe passes on component tests.
• npm run lint reports no accessibility violations.
• Lighthouse accessibility score is ≥ 90.
• Keyboard navigation reaches all interactive elements with visible focus indicators.
• VoiceOver/NVDA can navigate key application flows.

Closes #184

[Xuccessor]

Nice work on the accessibility pass, @0xVida! 🎉 The a11y code, tests, and test config (jest-axe + jsx-a11y + focus/contrast tweaks) all look solid, and CI is green across the board.

Holding back on the merge for one housekeeping reason: the +13k diff is largely generated lhr-*.json / lhr-*.html Lighthouse reports and heavy package-lock.json churn that shouldn't land in this PR. Could you:

• add lhr-* to .gitignore and remove those generated files from the commit
• prune unrelated package-lock.json updates
• keep just the a11y code, specs, and config changes

Once that's cleaned up I'll merge right away. 🙏

[Xuccessor]

Hey 👋 Accessibility and test additions look great. There's a merge conflict against main blocking this right now — could you rebase and push an update? I'll merge as soon as it's clean.

[Xuccessor]

Hey @0xVida — really appreciate the a11y work! Branch has merge conflicts with main right now — could you rebase and re-run CI? Once green we will get this in.

[Xuccessor]

Hey @0xVida — really appreciate the a11y work! Branch has merge conflicts with main right now — could you rebase and re-run CI? Once green we will get this in.

[Xuccessor]

Thanks for this. The branch has real merge conflicts with main right now and won't merge cleanly — could you rebase against the latest main and push? Once it's clean I'll be glad to merge.