WIP: First iteration of Conversations UI; wire up new messages API.

[mathewjordan]

What does this do?

This iteration updates our handling of messages from the chat endpoint web socket. Some notes:

• Types for streaming messages are redefined!
• On components/Chat/Response/Response.tsx we are handling for token, answer, tool_start, search_result, and final_message. aggregation_result Is not yet doing anything, nor are we doing anything with the intermittent start and stop messages.
• The interstitials rendering for the tool_start all utilize the same icon, but this could be extended to other SVGs as we refine this further.
• IMPT this does not yet handle a continued conversation
• We are now storing the completed rendered response in state once the final_message comes through.
• Some tests are ignored as we iterate.

How should we review?

1. Go to https://preview-5322-conversations-ui.dc.rdc-staging.library.northwestern.edu/search, OR spin up dev locally and set your environment:

NEXT_PUBLIC_DCAPI_ENDPOINT=https://dcapi-prototype.rdc-staging.library.northwestern.edu/api/v2

2. Do a few searches.
3. Conversations should roll in.
4. New searches should reset response view as expected.

[mbklein]

This is fantastic.