Design architecture for MAPLE chatbots

Identify tech stack and design philsophy for chatbot interfaces on MAPLE.

Example use case:
* Testimony drafting assistant
* Bill / policy issue question answering chat

Expectations about tech stack:
* ReAct AI agent with tool calling and reasoning loop capability
* Access to firebase vector index search (initially including indices for testimony, bills, and ballot questions -- later to include hearing transcripts and more)
* Lightweight frontend components that can be integratd in multiple places on frontend
* Ability to cap usage / costs and differentiate between logged in and not-logged in users