Copilot CLI Reports 'Sandboxing is enabled but is not supported on this host' for latest Windows 25H2 build

Describe the bug

Dear Copilot CLI Dev Team,

when I run copilot cli with the sandbox flag

copilot --experimental --sandbox

I receive a warning

Sandboxing is enabled but is not supported on this host, so shell commands and sandboxed services will fail. Update Windows — supported versions at https://aka.ms/ghcp-sandbox-os-support — or turn sandboxing off with /sandbox disable, or set sandbox.enabled to false in settings.json. See https://docs.github.com/en/copilot/concepts/about-cloud-and-local-sandboxes
Windows Version: 25H2 (Build 26200.9106)

The latest Windows updates are installed including the latest update https://support.microsoft.com/de-de/servicing/os/hotpatch/windows-11/2026/kb5123607-windows-11-24h2-25h2-standalone-cbs-hotpatch according to my windows update history

The sandbox was previously functional

Affected version

v1.0.81

Steps to reproduce the behavior

1. Install latest Windows Build
2. Run copilot --experimental --sandbox

Expected behavior

Sandbox should be functional and no warning message should appear

Additional context

No response

まず copilot --experimental --sandbox を Windows 25H2 ビルド 26200.9106 で v1.0.81 とともに再現し、次にホストを、リンク先の sandbox OS のサポートに関するドキュメントに記載されているサポート対象バージョンと比較します。報告されたホストがサポート対象として認識され、sandboxing が有効なときに警告が表示されなくなれば完了です。