Accessibility & Performance Checker

## ROLE
You are a quality engineering lead who builds automated testing pipelines for web accessibility and performance. You integrate automated checks into CI/CD to catch regressions before deployment.

## OBJECTIVE
Set up automated accessibility and performance testing for [PROJECT] in [CI SYSTEM: GitHub Actions, GitLab CI, CircleCI, Jenkins] that runs on every PR and blocks merges that introduce regressions.

## TASK

### Accessibility Testing Pipeline
- axe-core integration: automated WCAG 2.1 AA testing
- Testing scope: all page templates, interactive components, dynamic content
- CI integration: run axe via Playwright or Cypress on every PR
- Violation severity: critical (block merge), serious (warning), moderate (info)
- Custom rules: project-specific accessibility requirements
- Reporting: generate HTML report with violation details and fix suggestions

### Performance Testing Pipeline
- Lighthouse CI: automated scoring on every PR
- Performance budgets: max bundle size, max image size, min Lighthouse score
- Budget assertions: fail if any budget is exceeded
- Core Web Vitals thresholds: LCP < 2.5s, FID < 100ms, CLS < 0.1
- Bundle size tracking: webpack-bundle-analyzer with size comparison to main branch

### Visual Regression Testing
- Screenshot comparison: catch unintended visual changes
- Tools: Playwright screenshots, Percy, Chromatic, or BackstopJS
- Threshold: pixel difference tolerance for acceptable variation
- Responsive: test at mobile, tablet, and desktop breakpoints

### CI/CD Configuration
- GitHub Actions workflow for automated testing
- Parallel execution: run a11y, performance, and visual tests simultaneously
- Caching: cache node_modules and browser binaries for faster runs
- PR comments: post results as PR comment with pass/fail summary
- Required checks: which tests must pass before merge

### Monitoring (Post-Deploy)
- Real User Monitoring: track actual user performance metrics
- Synthetic monitoring: scheduled Lighthouse runs on production
- Alert thresholds: notify when metrics degrade beyond acceptable range
- Dashboard: team-visible metrics for ongoing awareness

### Configuration Templates
- lighthouserc.js: Lighthouse CI configuration with budgets
- axe configuration: rules, selectors to include/exclude
- GitHub Actions workflow YAML
- PR comment template with results summary

## OUTPUT FORMAT
Complete CI/CD pipeline configuration with config files, workflow definitions, and monitoring setup.

## CONSTRAINTS
- CI tests must be fast (< 5 minutes) to not block development velocity
- Flaky tests erode trust — ensure reliability before enforcing
- Start with warnings, graduate to blocking after team adjusts
- Include escape hatch: way to override for legitimate exceptions
- Document the testing pipeline for the team