Improved old session cleanup

### Short summary

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### Affected version or release

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### Installation context

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### What happened?

Right now, it's very difficult for those of us running multiple sessions to clean up our app due to the amount of sessions being created. It also leads to significant bloat with retained work trees.
To resolve this, we should:
1. introduce an auto-archive functionality to clean up past chats (and eventually delete)
2. add ability to archive/delete multiple sessions with shift key

### Steps to reproduce

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### Expected behavior

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### Additional context

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