dixie: new host — Aurora R11 helper-tier inference node

Alienware Aurora R11 (i7-10700, 64 GB, one RTX 3060 12 GB today; second card
when its fans are replaced). Headless, Wi-Fi only, unencrypted root by
decision (always-on box that must come back from a power cut unattended).

- llama.cpp router (CUDA, from unstable) on :11434 with the three helper
  models resident (--models-max 3): ornith 9B for the Hermes approval guardian
  / title / web_extract and Honcho deriver, qwen3-4b for Honcho dialectic,
  Qwen3-Embedding-0.6B for Honcho embeddings. Vision (qwen3-vl-8b) on its own
  on-demand server on :11433 since it does not fit beside them in 12 GB.
- Both servers tailnet-only (tailscale0 firewall); GPUs capped at 140 W
  (thermal hour 2026-09-21: 75 C plateau, no throttling).
- Model weights on the USB cache stick (ext4 label dixie-cache) bind-mounted
  into /var/lib/llama-server/models; filled from straylight with dixie-push.
- 6.12 LTS kernel (mt7921u for the AX9L USB Wi-Fi arriving 2026-09-24).
- SSH keys baked in: no console after install to add them from.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

hw/dixie/hardware-configuration.nix

@@ -0,0 +1,18 @@
+# Do not modify this file!  It was generated by ‘nixos-generate-config’
+# and may be overwritten by future invocations.  Please make changes
+# to /etc/nixos/configuration.nix instead.
+{ config, lib, pkgs, modulesPath, ... }:
+
+{
+  imports =
+    [ (modulesPath + "/installer/scan/not-detected.nix")
+    ];
+
+  boot.initrd.availableKernelModules = [ "xhci_pci" "ahci" "nvme" "usbhid" "usb_storage" "sd_mod" ];
+  boot.initrd.kernelModules = [ ];
+  boot.kernelModules = [ "kvm-intel" ];
+  boot.extraModulePackages = [ ];
+
+  nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
+  hardware.cpu.intel.updateMicrocode = lib.mkDefault config.hardware.enableRedistributableFirmware;
+}