make pathways into an API

[artifishvr]

todo prose

abstract away all of SpongeLLM personality and code and make pathways itself an api

[hyd3rs]

note: as discussed in the spongeass discord, pathways engine would include all of the conversation (for history & separation) & integration logic. i want to make it so starting a new conversation would also require specifying a custom prompt set, leaving open the possibility for making SpongeLLM's personality spongeass-only