feat: consolidate Build #5 kernel qualification, CoCo allocation, and legacy service hardening

[emersonbusson]

Consolidates the WSL2 Linux Kernel Build #5 qualification (6.18.40.1-microsoft-standard-WSL2+) with 100% 3-tier cascade saturation (ZRAM + VRAM + SSD), Confidential Computing (CoCo) vmbus_alloc_buffer chunked allocation safety, autonomous host origin VHDX attachment, and legacy service safety regression protections.