Add support for Windows Server 2025

Overview

Add support for Windows Server 2025

Windows Server 2025 is the Windows Server version released as generally available on 2024-11-01 and is the server version of Windows 24H2 LTSC (the client-focused Long-Term Servicing Channel version of Windows 11).

Implementation Tasks

1. Add ltsc2025 to support list for Docker executor
2. Create a new helper image based on ltsc2025-amd64 and build with CI
3. Run ltsc2025-amd64 tests on main, similar to 1903/1909