Add CI/CD Pipeline with Build Artifacts for React Application

[Copilot]

This PR implements a comprehensive CI/CD pipeline for the CoreTex project, transforming it from a standalone HTML application to a modern React build system with automated testing and deployment capabilities.

🚀 What's New

CI/CD Pipeline

Added a complete GitHub Actions workflow (.github/workflows/ci.yml) that:

• Tests across multiple Node.js versions (18.x, 20.x) to ensure compatibility
• Runs comprehensive test suite with Jest and React Testing Library (10 tests covering all components)
• Performs code quality checks with ESLint to maintain code standards
• Builds optimized production artifacts using Vite bundler
• Uploads build artifacts to GitHub Actions for easy download and deployment
• Creates preview deployments for pull requests using GitHub Pages
• Runs security scans with npm audit and dependency review

Modern Build System

Implemented a Vite-based build configuration that generates:

• Optimized React bundle (~146KB JavaScript, ~0.6KB CSS)
• Vendor chunk separation for better caching (React/ReactDOM isolated)
• Source maps for debugging support
• Gzipped assets reducing total size to ~48KB compressed

Project Structure Modernization

• Added package.json with proper React 18 dependencies and build scripts
• Configured Jest testing with jsdom environment and CSS import mocking
• Set up ESLint with React-specific rules and hooks linting
• Created Vite configuration for optimal development and production builds
• Reorganized entry points (moved from main.js to main.jsx for proper JSX handling)

🧪 Testing Results

All existing functionality is preserved and now properly tested:

Test Suites: 8 passed, 8 total
Tests:       10 passed, 10 total

The test suite covers:

• App component rendering and language switching
• Dashboard metrics display
• FaceRecognition component functionality
• AnomalyLog display logic
• LanguageSwitcher behavior
• Internationalization features

📦 Build Artifacts

The CI pipeline now generates deployable artifacts:

• dist/index.html - Optimized entry point
• dist/assets/index-*.js - Application bundle with tree-shaking
• dist/assets/vendor-*.js - React framework code (cached separately)
• dist/assets/index-*.css - Minified styles

🔧 Development Workflow

New npm scripts for development:

npm run dev        # Start development server
npm run build      # Create production build  
npm run test       # Run test suite
npm run lint       # Check code quality

📚 Documentation Updates

• Updated README.md with build badges, quick start guide, and development instructions
• Revised filstruktur.md to reflect the new project structure
• Preserved original standalone version as index_legacy.html

The pipeline maintains backward compatibility while providing a modern development experience and automated quality assurance for future contributions.

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.