Unclear what mode I'm in from command center chat

[bamurtaugh]

Ref https://github.com/microsoft/vscode-internalbacklog/issues/6527

A few thoughts as I've been using the command center chat entry point in the agent / artifact first view:

• I expected an indicator of the mode I'm in (agent/ask/plan)
• I wanted a way to + a new chat
• I expected the background and cloud options not to be available in an empty workspace, unless we were also going to provide the repo picker dropdown
  • 

[bamurtaugh]

Some other feedback I had and we're starting to hear from others: it's unclear what the number count is for unread sessions (it's just a number alone, no label or hover tooltip info)