Given that now fetch_web_url_raw can also fetch local files, if local
file access scheme is enabled in simpleproxy.py, so rename this
tool call by dropping web from its name, given that some ai models
were getting confused because of the same.
By default ensure external_ai tool call related special chat session
starts with tool calls disabled and client side sliding window of 1.
Add a helper in SimpleChat class to set these along with clearing of
any chat history.
Inturn now give the user flexibility to change this from within
the program, if they need to for what ever reason, till the program
restarts.
hanishkvc