- Delete unused ResponseNormalizer class and its initialization logic
- Remove response_normalizer and enable_response_normalization parameters from handlers
- Simplify chat adapter base initialization by removing normalizer setup
- Clean up unused imports in handler modules
- Add extract_cache_creation_tokens utility to handle new/old cache creation token formats
- Implement defensive update strategy in StreamContext to prevent zero values overwriting valid data
- Simplify cache creation token parsing in Claude handler using new utility
- Add comprehensive test suite for cache creation token extraction
- Improve type hints in handler classes