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/disk-config.nix

@@ -0,0 +1,38 @@
+## (dixie) disko config
+## Alienware Aurora R11: Samsung PM9A1 1 TB NVMe is the system disk. The 6 TB SATA HDD and the
+## USB cache stick are left alone here (the stick is mounted by label in default.nix).
+## Unencrypted on purpose: headless box that must come back from a power cut with nobody
+## at the console to unlock it.
+
+{ lib, ... }:
+
+{
+  disko.devices.disk.main = {
+    type = "disk";
+    device = "/dev/disk/by-id/nvme-eui.36355630521205220025384500000001";
+    content = {
+      type = "gpt";
+      partitions = {
+        ESP = {
+          size = "1G";
+          type = "EF00";
+          content = {
+            type = "filesystem";
+            format = "vfat";
+            mountpoint = "/boot";
+            mountOptions = [ "umask=0077" ];
+          };
+        };
+        root = {
+          size = "100%";
+          content = {
+            type = "filesystem";
+            format = "ext4";
+            mountpoint = "/";
+            mountOptions = [ "noatime" ];
+          };
+        };
+      };
+    };
+  };
+}