Add ability to build JBrowse configs from a user-submitted description

[carolinebridge]

It may be useful to expand the functionality of the bot to include creating configuration files for users based on a description of what kind of assemblies, tracks, etc. they want. This could be the entire config file, but perhaps we could start with just a section of the config, e.g.:

Add a default session to my config file wherein track_A is open on a LinearGenomeView and the Track selector widget is open

Other applications of such an interface could be a conversation with the bot explaining config files in more detail, what to change about a config file if it isn't working properly; etc.

Routing was previously attempted to be integrated into the solution for task delegation between config discussion and general JBrowse knowledge, but did not work due to the use of LangGraph for history maintenance.

It may be fruitful to leverage separate retrievers to accomplish this task, and perhaps separate out the existing JBrowse general questions vs. config questions that is presently achieved through a thorough system prompt.