fix: bypass fsmonitor for mutation evidence

A stale repository fsmonitor daemon can block the pre-spawn mutation snapshot indefinitely, so the child never starts. This bypasses fsmonitor only for the read-only tracked-diff commands that collect mutation evidence.

Thanks to [@jpriverar](https://github.com/jpriverar) for #1497.

Gate: exact-head fresh review clean; Ubuntu, Windows, bun workflow, and Greptile passed on 246d7870188d747e854a521fe8758abe6c775214.