Session workspace mismatch when forked

### Short summary

_No response_

### Affected version or release

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### Installation context

_No response_

### What happened?

When forked and unlinked, the session's workspace and the actual forked workspace does not match

### Steps to reproduce

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### Expected behavior

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### Additional context

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The issue names no files, tests, or entry points and provides no reproduction steps. Start by reproducing the fork-and-unlink flow, then trace where the session workspace and forked workspace are recorded or resolved; done means both refer to the same workspace after unlinking.

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