feat(dom): Add Dominican Republic cédula validator

[AngusHsu]

Description

Add support for Dominican Republic Cédula de Identidad y Electoral.

Parent Epic

#14 - Add support for new countries

Dominican Republic Cédula Format

• 11 digits
• Format: NNN-NNNNNNN-N
• Check digit using Luhn algorithm

Tasks

• Research and verify format
• Create src/countries/dom/ directory
• Implement Cedula validator class
• Implement validate() with Luhn checksum
• Implement parse() function
• Add to main dispatcher
• Add to getCountryIdFormat()
• Write comprehensive tests (80%+ coverage)

Acceptance Criteria

• Validation works correctly
• Luhn checksum implemented
• Test coverage 80%+

Labels

enhancement, new-country, dominican-republic