- Add limit and score_threshold to BaseRagConfig, propagate to clients
- Update default search params in RAG storage, knowledge, and memory (limit=5, threshold=0.6)
- Fix linting (ruff, mypy, PERF203) and refactor save logic
- Update tests for new defaults and ChromaDB behavior
- Sanitize ChromaDB collection names and use original dir naming
- Add persistent client with file locking to the ChromaDB factory
- Add upsert support to the ChromaDB client
- Suppress ChromaDB deprecation warnings for `model_fields`
- Extract `suppress_logging` into shared `logger_utils`
- Update tests to reflect upsert behavior
- Docs: add additional note
### RAG Config System
* Added ChromaDB client creation via config with sensible defaults
* Introduced optional imports and shared RAG config utilities/schema
* Enabled embedding function support with ChromaDB provider integration
* Refactored configs for immutability and stronger type safety
* Removed unused code and expanded test coverage
