Add a composable devkit extension (shell-enabled busybox) cold-plugged
alongside the NVIDIA base and gpu images so kata-runtime exec works without
rebuilding the shell-less production rootfs. Wire build and packaging,
runtime-rs drop-in examples, guest_extension_images append merge, kata-deploy
debug cold-plug with dm-verity params, and agent console shell lookup at
/run/kata-extensions/devkit.
Devkit bin/sh and devkit-apt wrappers use a shebang pointing at the
extension busybox (not /bin/sh): the NVIDIA base rootfs is shell-less, so
kernel shebang resolution against the guest root would fail and debug
console sessions would drop immediately.
Signed-off-by: Fabiano Fidêncio <ffidencio@nvidia.com>
Assisted-by: Cursor <cursoragent@cursor.com>
6ee03d1571