When copilot crashes with enqueued messages, you lose them

### Describe the bug

I had a copilot session running and it crashed. When I resume it, the queued messages are no longer there and copilot doesn't know anything about them. In theory, I can use the arrow keys to go back through history to find them, but I've been using several other sessions and their messages show now too. I don't remember what specific messages I had in the queue.

### Affected version

GitHub Copilot CLI 1.0.43

### Steps to reproduce the behavior

Start a session
Queue several messages
Something happens that causes copilot to crash
Resume the session
Copilot doesn't know about the previously queued messages

### Expected behavior

Copilot can restore the queue messages somehow.

### Additional context

Windows 11 x64

Start by reproducing the crash after queuing several messages, then trace the session resume and queued-message handling entry points. Confirm where queued messages are lost and verify that resuming a crashed session restores them without mixing messages from other sessions.

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