Render "AI Changes" node in SCM

[alexdima]

I often forget to act on AI changes (i.e. Keep/Discard) and I end up committing files which still have pending decisions. I often even create PRs and then the Keep/Discard state sticks around for a long time, up until I create a new chat.

It would be interesting to explore:

• rendering unconfirmed AI changes in the SCM viewlet
• automatically marking "keep" for AI changes that are staged

To clarify, I am not arguing for changing the way things work, but rather to surface the existing data also in the SCM viewlet. The existing data can be reached via IChatEditingService > IChatEditingSession > entries

fyi @joaomoreno