Notebook aware chat

[brichet]

The chat model should be aware of the current Notebook, and be able to interact with the corresponding kernel.

This is one of the idea proposed in jupyterlab/jupyter-ai#1157, which could significantly increase the chat and the AI experience.

Problem

The chat make use of the current cell (in a Notebook widget) and current selection (in any Document widget), but do not use the active Notebook (or active Document).

Proposed Solution

The active cell manager already uses the Notebook tracker to catch the current cell.
This manager could be updated to get both active cell context (content, id...) and Notebook context (kernel and/or variables, all cells...).

Additional context

See jupyterlab/jupyter-ai#1157 for more context about this feature.

Additional question

• Should the chat be tied to one Notebook or/and aware of the current Notebook ?

  from Revamped Jupyter AI jupyter-ai#1157 (comment)

  Note: The v3-dev branch already supports multiple chats in the same session. I will start working with others to explore if these files can be "tied" to a notebook to provide the "per-notebook chat" idea proposed here.

  This would probably need some UX design to make both options available.
  Users may be confused about the Notebook/kernel they are interacting with, if the chat can be tied to one specific Notebook or be aware of the current Notebook.