Issue 9: Add Testing and Quality Assurance

## Overview
Implement comprehensive testing and quality assurance measures.

## Tasks
- [ ] Add unit tests for components
- [ ] Implement integration tests
- [ ] Add end-to-end tests
- [ ] Set up automated testing pipeline
- [ ] Add code coverage reporting
- [ ] Implement accessibility testing
- [ ] Add performance testing
- [ ] Set up error monitoring
- [ ] Add security testing
- [ ] Implement code quality checks

## Acceptance Criteria
- [ ] Test coverage is above 80%
- [ ] All critical paths are tested
- [ ] Automated testing runs on PRs
- [ ] Performance meets requirements
- [ ] Security vulnerabilities are addressed

## Technical Details
- Use Jest and React Testing Library
- Implement Playwright for E2E tests
- Set up GitHub Actions for CI/CD
- Add SonarQube for code quality
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No files, tests, or entry points are named. Start by inspecting the TypeScript React project and its existing test and CI configuration, then determine how the requested Jest, React Testing Library, Playwright, GitHub Actions, coverage, accessibility, performance, security, and SonarQube work fits together. Done means the listed acceptance criteria are met.

Written by the indexing model from the issue text.