NVIDIA GPU Driver

Host-level NVIDIA driver (580.126.18 LTSB) installed via the `.run` installer since the Debian 13 apt packages don't support kernel 6.17. nvidia-persistenced keeps `/dev/nvidia*` device nodes alive for container GPU passthrough — without it, containers lose GPU access after idle periods. DKMS ensures the kernel module rebuilds automatically on kernel updates. Currently shared with Jellyfin for hardware transcoding (NVENC H.264, HEVC, AV1).