feat: Add link checker and enhance CLI tools

- Add comprehensive link checker for testing archive accessibility
  * Check main site, Traefik dashboard, and all 23 archives
  * Generate JSON reports with detailed results
  * Configurable timeout and base URL
  * CLI interface with --url and --timeout parameters

- Enhance CLI with Docker management commands
  * docker-up, docker-down, docker-ps, docker-logs
  * Integration with docker-compose commands
  * User-friendly output with emojis and status messages

- Add generate-compose command to CLI
  * Automatically detect festival folders
  * Recognize SPA frameworks (archives 20-23)
  * Apply correct nginx configurations

- Update generate-compose.js configuration
  * Fix maxArchive: 25  23 (match actual archives)
  * Fix spaArchives: [21-25]  [20-23] (correct range)
  * Update nginx config reference to current deployment

- Convert link-checker.js to ES modules
  * Replace require() with import statements
  * Replace module.exports with export default
  * Add proper ES module detection for CLI execution

- Add comprehensive documentation
  * CLI-TOOLS.md - Complete CLI tools reference
  * CHANGELOG-CLI.md - Detailed changelog
  * Update README.md with Docker hosting section

- Add testing utilities
  * test-integration.js - Integration tests for all features
  * quick-link-check.js - Fast check of selected archives
  * test-link-checker.js - Basic functionality test

- Update package.json scripts
  * docker:ps - Show container status
  * links:check - Full link checking
  * links:quick - Quick check of selected archives
  * links:test - Test basic functionality

All integration tests passing (5/5)