Add safe Windows/Linux pointer lab

[junaga]

What

• Add a safe, headless Windows/Linux pointer conformance lab with one-command lifecycle control.
• Replay identical reports through two synthetic USB HID mice into simultaneous Windows and Linux VMs, collect native guest events, and compare exact movement results.
• Add a native Windows Raw Input collector, Hyprland tracing, timing analysis, VM provisioning/repair, screenshots, and Bluetooth adapter diagnostics.
• Quarantine full PCI xHCI passthrough behind an explicit unsafe opt-in so normal lab commands never detach the host's USB controller.

Why

The previous physical-controller experiment could disconnect every host USB device and depended on brittle fixed VNC/session assumptions. This provides a practical automated path for isolating pointer algorithm differences without taking over host hardware, while preserving explicitly guarded tools for later real Bluetooth/USB validation.

Validation

• lab/pointer-lab.sh test lab/traces/full-scenarios.csv: 30/30 exact scenarios; both guests ended at (385,18); host-write skew median 0.022 ms, p95 0.030 ms, max 0.033 ms.
• ctest --test-dir build/dev --output-on-failure: 18/18 passed.
• bash -n lab/*.sh lab/unsafe/*.sh
• xmllint --noout lab/guest/windows/Autounattend.xml
• git diff --cached --check

Latest dual-VM artifacts were generated locally at build/lab/dual-vm-20260728T123753Z.