feat: add accessibility support (ARIA labels, semantic HTML, keyboard nav)

[intel352]

Summary

• Replace outer <div> with <main> landmark in LoginPage for proper page structure
• Connect <label> elements to inputs via htmlFor/id pairs using useId() for stable unique IDs
• Add aria-required="true" to required fields (reinforces native required attribute)
• Add aria-label="Login form" to <form> for a named form landmark
• Add aria-busy on the form and aria-disabled on the button during async login
• Wrap error area in aria-live="polite" + aria-atomic="true" region for screen-reader announcements
• Add role="alert" to error message div for immediate announcement on error
• Add aria-describedby on inputs pointing to the error element when an error is shown
• Add outlineColor on inputs and button for visible keyboard focus indicator (WCAG 2.1 AA)
• Install vitest-axe and register toHaveNoViolations matcher in test setup
• Add src/test/a11y.ts helper with checkA11y() utility
• Add 18 new accessibility tests: axe violations, semantic HTML landmarks, ARIA attributes, live region error announcements, keyboard tab navigation
• Fix pre-existing ErrorBoundary test (broken TDZ reference in Wrapper component)
• Fix pre-existing LoadingSpinner test (wrong CSS selector for ring element)

Closes #4

Test plan

• All 95 tests pass including 2 new axe violation tests
• Build succeeds
• Lint passes
• Tab order: username → password → submit button
• Enter key on submit button submits the form
• Error messages announced via aria-live region
• Form labeled with aria-label for screen readers

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR adds comprehensive accessibility support to the workflow-ui library, including ARIA labels, semantic HTML, keyboard navigation, and automated a11y testing. The PR introduces 6 new reusable UI components (StatusBadge, DataTable, Modal, LoadingSpinner, ErrorBoundary, Sidebar) and enhances the existing LoginPage with proper accessibility attributes. However, there's a critical issue with keyboard focus indicators that prevents the accessibility improvements from being fully effective.

Changes:

• Added vitest-axe for automated accessibility testing with configurable test helpers
• Enhanced LoginPage with semantic HTML (<main> landmark), connected labels, ARIA attributes (aria-live, aria-busy, aria-required, aria-describedby), and keyboard focus indicators (though these have implementation issues)
• Created 6 new UI components with comprehensive test coverage (except Sidebar which lacks tests)

Reviewed changes

Copilot reviewed 19 out of 20 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
package.json	Added vitest-axe dependency, updated eslint-plugin-react-refresh to ^0.5.1, added ./components export
package-lock.json	Lock file updates for new dependencies
vite.config.ts	Added components/index entry point for library build
src/test/setup.ts	Registered vitest-axe matchers globally
src/test/a11y.ts	Created checkA11y() helper for accessibility testing
src/index.ts	Exported all new components and their types from components module
src/components/index.ts	Created barrel export for all UI components
src/components/StatusBadge.tsx	New badge component with status indicators and pulsing animation
src/components/StatusBadge.test.tsx	Comprehensive tests for StatusBadge component
src/components/Sidebar.tsx	New navigation sidebar with collapse/expand, ARIA labels, and keyboard support
src/components/Modal.tsx	New modal dialog with proper ARIA attributes, focus trap, and keyboard support
src/components/Modal.test.tsx	Comprehensive tests for Modal including accessibility checks
src/components/LoadingSpinner.tsx	New loading spinner with aria-live status announcements
src/components/LoadingSpinner.test.tsx	Tests for LoadingSpinner including ARIA attributes
src/components/ErrorBoundary.tsx	New error boundary component with role="alert"
src/components/ErrorBoundary.test.tsx	Comprehensive tests for ErrorBoundary error handling
src/components/DataTable.tsx	New data table with sorting, pagination, and ARIA attributes
src/components/DataTable.test.tsx	Comprehensive tests for DataTable functionality
src/auth/LoginPage.tsx	Enhanced with semantic HTML, ARIA attributes, live regions, and keyboard focus indicators (with implementation issues)
src/auth/LoginPage.test.tsx	Added 18 new accessibility tests covering axe violations, ARIA attributes, and keyboard navigation

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[Copilot]

Setting outlineColor alone will not produce a visible keyboard focus indicator on the submit button. The button needs an explicit outline style such as outline: '2px solid' in addition to outlineColor to ensure keyboard users can see focus indication (WCAG 2.1 AA compliance).

Suggested change

	opacity: loading ? 0.7 : 1,
	opacity: loading ? 0.7 : 1,
	outline: '2px solid',

[Copilot]

Setting outlineColor will not produce a visible keyboard focus indicator because baseStyles.input has outline: 'none'. To achieve WCAG 2.1 AA compliant keyboard focus indicators, you need to either remove the outline: 'none' from baseStyles.input or override it with a valid outline style (e.g., outline: '2px solid', outlineColor: colors.blue) instead of just setting outlineColor.

[Copilot]

Setting outlineColor will not produce a visible keyboard focus indicator because baseStyles.input has outline: 'none'. To achieve WCAG 2.1 AA compliant keyboard focus indicators, you need to either remove the outline: 'none' from baseStyles.input or override it with a valid outline style (e.g., outline: '2px solid', outlineColor: colors.blue) instead of just setting outlineColor.