- Add enable_semantic_segmentation: bool field with default=True
- Allow override via KB_ENABLE_SEMANTIC_SEGMENTATION env var
- Pydantic automatically parses boolean strings (true/false, yes/no, 1/0)
- Update docstring to document new field
CONFIG-01: LLM segmentation can be enabled/disabled via configuration
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>