Compaction killed the session

### Describe the bug

While a task running, I see this in the logs:

> ● Compaction completed
> │ A new checkpoint has been added to your session.
> └ Use /session checkpoints 3 to view the compaction summary.
>
> ◐ The user hasn't sent a new message yet - the system just loaded the context summary. Let me wait for the user's actual question/request.
> ...
> Session restored. Here's the current state:

And then it just stopped and asking

> What would you like to do next?

And I need to repeat my request!

### Affected version

_No response_

### Steps to reproduce the behavior

_No response_

### Expected behavior

_No response_

### Additional context

_No response_

The report names no files, tests, or entry points. Start by reproducing the session-compaction and restoration flow, then trace the logs around checkpoint loading; done means explaining why the original request is lost after restoration and verifying that the behavior is covered by a regression test.

Written by the indexing model from the issue text.