AurealNix v0.4.1 — USB printer support

Maintenance respin of v0.4. The only change is the kernel, now
6.18.44-g61025ec85b88, which adds — at a user's request — support for
USB printers:

• usblp (USB printer class driver): creates /dev/usb/lp0 when a USB
  printer is plugged in, so CUPS and firmware downloaders like foo2zjs
  (legacy GDI laser printers) work out of the box.
• The parallel port stack as modules (parport with IEEE-1284 support,
  lp, ppdev, parport_uss720) for USB-to-parallel adapters that
  expose a raw parallel port. Nothing loads unless matching hardware is
  plugged in.

Everything else is identical to v0.4 (same userspace, same fixes, same
known WireGuard saturation issue). If you're already on v0.4 and don't
need a printer, there's no reason to reflash.

Images (sha256 checksums attached):

• aurealnix-opi4a-debian13-cli-v0.4.1.img.xz — CLI / headless
• aurealnix-opi4a-debian13-gnome-v0.4.1.img.xz — GNOME (Wayland)
• aurealnix-opi4a-ubuntu2604-kubuntu-v0.4.1.img.xz — Kubuntu 26.04 / KDE Plasma