Restore repeatable VirGL/SPICE startup on iPadOS 27

[theos2node]

The current reliable device build uses VGA/VNC. Re-enabling virtio-gpu-gl stalls inside qemu_init before QMP or serial becomes available.

Acceptance:

• five consecutive physical-device boots reach QMP and guest serial;
• guest reports VirGL hardware rendering rather than llvmpipe;
• local SPICE presents frames without a process exit;
• metrics and sanitized logs identify the fixed initialization stage.