fix(agentos): route CompareVmConfig through the sidecar request loop

[eersnington]

• Hosts call CompareVmConfig to decide whether a config change needs a VM restart.
• The stdio request loop handles CreateVm and DisposeVm itself and sends every other request through prepare_request_wire. CompareVmConfig was not prepared there, so it failed with ERR_AGENTOS_UNPREPARED_REQUEST_ROUTE. Every config change on a running VM failed.
• CompareVmConfig is now prepared like ListMounts.
• Adds crates/client/tests/vm_config_compare_e2e.rs, which compares configs through a real sidecar.

RequestRoute::CompareVmConfig(payload) => {
    let result = self.compare_vm_config(&request, payload);
    Ok(Some(PreparedRequest::from_future(request, async move { result })))
}

Code: crates/native-sidecar/src/service.rs

---

This is part 4 of 4 in a stack:

•  4  fix(agentos): route CompareVmConfig through the sidecar request loop #2018 👈
•  3  perf(agentos): batch chunked_sqlite index saves into transactions #2017
•  2  fix(agentos): keep chunked_sqlite metadata pieces under the remote SQLite bind limit #2016
•  1  fix(agentos): accept [ as a package command name #2015

[the-company-company]

🟠 1 medium-severity finding

_{Reviewed commit cc0e7d4.}

[the-company-company]

✅ No issues found

_{Reviewed commit 5dc8eb0.}