docs: add comprehensive transformer documentation in English and Portuguese

This commit adds detailed documentation for the KaririCode Transformer component in both English and Brazilian Portuguese. The documentation includes:

- Complete usage examples with output samples
- Detailed configuration options for each transformer
- Real-world examples with practical applications
- Code samples for common transformation scenarios

Documentation highlights:
- String transformation (case, mask, slug)
- Data formatting (dates, numbers, currency)
- Array manipulation (flattening, grouping, key mapping)
- Template processing with examples
- Integration examples with other KaririCode components

The documentation is structured to serve both international and Brazilian developers, with:
- Localized examples
- Regional formatting patterns
- Culturally appropriate use cases

Files added:
- README.md (English version)
- README.pt-BR.md (Portuguese version)

Author: walmir-silva