Support Follow-Up Questions in User Chat Page

[mdr223]

When users ask follow-up questions in the User Chat, currently:

1. (I believe) previous execution traces / output are not provided as input / context to the follow-up query
2. There is a long delay before the follow-up query execution kicks off

Let's try to make the execution of follow-up queries as seamless as possible to support user iteration on their queries.

[mdr223]

Closed by #124