feat: add Jest matchers with global configuration and e2e testing

[ike18t]

Summary

This PR adds comprehensive Jest matcher support for testing WireMock interactions, along with e2e testing infrastructure and improved build configuration.

✨ New Features

Jest Matchers

• toHaveBeenRequested(options?) - Verify stub received at least one request
• toHaveBeenRequestedWith(expected, options?) - Verify stub received request with specific payload
• toHaveBeenRequestedTimes(expectedCount, options?) - Verify stub received exact number of requests
• Built-in retry logic with configurable delays for async operations
• Global configuration via Configuration.setMatcherOptions()
• TypeScript support with proper type declarations

E2E Testing

• Testcontainers integration for real WireMock server testing
• Comprehensive test coverage for all matcher functionality
• Complex payload testing with nested JSON objects
• Request counting and verification scenarios

Developer Experience

• Separate build configuration (tsconfig.build.json) for clean artifacts
• Improved ESLint configuration with proper ignores
• Comprehensive documentation with examples and API reference
• Maintained test file linting while excluding from builds

🔧 Technical Details

Configuration

// Global matcher defaults
Configuration.setMatcherOptions({
  retries: 10,  // Default: 15
  delay: 100    // Default: 200ms
});

// Per-matcher overrides
await expect(stubId).toHaveBeenRequested({ retries: 5, delay: 50 });

Usage Example

import { wiremockMapperMatchers } from 'wiremock-mapper';

expect.extend(wiremockMapperMatchers);

// Test endpoint was called with specific payload
await expect(stubId).toHaveBeenRequestedWith({
  name: 'John Doe',
  email: 'john@example.com'
});

📦 Breaking Changes

None - all changes are additive and backward compatible.

🧪 Testing

- All existing tests continue to pass
- Added 5 new e2e tests using testcontainers
- Test coverage maintained at >90%
- Linting passes for all files including test files

📚 Documentation

- Added comprehensive Jest matchers section to README
- Included setup instructions, API reference, and examples
- Added troubleshooting guidance
- Updated with global configuration options

🚀 Release Notes

This will be released as v0.7.1 with the following highlights:
- Jest matchers for improved testing experience
- E2e testing infrastructure
- Enhanced developer tooling
- Comprehensive documentation updates