Chat sidebar panel

[mscolnick]

Description

We should have a fully functioning chat sidebar panel, similar to vscode.

Suggested solution

1. Can ask AI a question
2. Include context such as dataframes and cells
3. Can create new threads and jump back to thread
4. Can edit the middle of a thread and fork
5. Any code blocks can be inserted in the notebook

Alternative

No response

Additional context

No response

[mscolnick]

Closed by #3919