Add redbear-usb-storage-check in-guest binary that validates USB mass
storage read and write I/O: discovers /scheme/disk/ devices, writes a
test pattern to sector 2048, reads it back, verifies match, restores
original content. Updates test-usb-storage-qemu.sh with write-proof
verification step.
Includes all accumulated Red Bear OS work: kernel patches, relibc
patches, driver infrastructure, DRM/GPU, KDE recipes, firmware,
validation tooling, build system hardening, and documentation.
