When resuming an old session the agent used in that old session is not selected

Describe the bug

I was in a session where I started with a specific agent (i.e. /agent x). I then resumed that session the next day and I had to select the agent again manually.

This is kind of hard to see if you don't pay close enough attention to it.

I'm also a bit unsure how big the impact is since the agent would already be in the history.

Affected version

1.0.80

Steps to reproduce the behavior

1. create a session
2. select agent /agent x (agent name should show up in the bottom bar)
3. use the session
4. /clear
5. /resume the old session
6. agent name is not shown in the bottom bar

Expected behavior

Agent that was using in the the resumed session should again be selected automatically.

Additional context

No response

Start by reproducing the issue in the Copilot CLI with /agent, /clear, and /resume as described. Trace how resumed sessions restore their state and how the selected agent is shown in the bottom bar. Done means resuming the session automatically selects and displays the agent that was active when the session was saved.