* 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