- Add ContextMerger class for combining local and external history
- Implement message fingerprint computation (SHA256 hash)
- Implement deduplication: local history takes priority
- Implement token-based truncation using tiktoken
- Add comprehensive unit tests (20 test cases)
- Add LLMClient abstract base class with generate/stream_generate interfaces
- Implement OpenAIClient with httpx for OpenAI-compatible API calls
- Add retry logic with tenacity for timeout handling
- Support both non-streaming and streaming generation
- Add comprehensive unit tests for LLM Adapter
- Fix entities.py JSON column type for SQLModel compatibility