- Language enum: en-US, en-GB, es, fr, hi, it, ja, pt-BR, zh
- Engine-specific mappings (kokoro → single-letter) live in pipeline_factory and synthesize
- spacy_utils uses Language enum keys for model mapping
- split_pattern uses Language enum properties (is_cjk)
- Updated all tests to use ISO codes
- Extract unified split pattern logic to domain/split_pattern.py
- Add get_split_pattern() function with language and subtitle_mode support
- Remove duplicated logic from pyqt/conversion.py
- Update pyqt/conversion.py to use domain.split_pattern.get_split_pattern
- Add tests/test_split_pattern.py with 20 tests covering English, CJK, Spanish, French, and pattern structure