* feat: support bots
* refactor with RoleLike
* improve exiting session
* make bot works with rag
* refactor repl assert state
* add bot banner
* repl complete bots according bots.txt
* fix on windows
* remove threadpool executing function callings
* adjust repl left_prompt
* move bot config to global config.yaml
* `.bot` throw err if funciton callings is not configured
* feat: support RAG
* support more embeddings models and implement concurrent embedding api
* show the progress of addings paths
* ignore embedding context when saving message
* embedding model max_chunk_size => default_chunk_size
* support pdf and pandoc formats (docx, epub, ipynb)
* feat: support function calling
* fix on Windows OS
* implement multi-steps function calling
* fix on Windows OS
* add error for client not support function calling
* refactor message data structure and make claude client supporting function calling
* support reuse previous call results
* improve error handling for function calling
* use prefix `may_` as indicator for `execute` type fucntions
1. automatically switch to the model that has the necessary capabilities.
2. throw an error if the client does not have a model with the necessary capabilities
* feat: support vision
* clippy
* implement vision
* resolve data url to local file
* add model openai:gpt-4-vision-preview
* use newline to concate embeded text files
* set max_tokens for gpt-4-vision-preview
