feat(hosts): example template host

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

hosts/example/hardware-configuration.nix

@@ -0,0 +1,44 @@
+# PLACEHOLDER hardware scan — REPLACE before building on real hardware:
+#   sudo nixos-generate-config --show-hardware-config > hardware-configuration.nix
+#
+# This generic stub exists only so the `example` host evaluates/builds as a
+# template (and so the template can't silently rot in CI). The by-label
+# devices below will NOT match your machine — a real scan captures your
+# actual disks, filesystems, kernel modules, and CPU microcode.
+#
+# hostPlatform is set by lib/mksystem.nix; the bootloader (systemd-boot)
+# by modules/boot.nix — so this file only needs filesystems.
+{
+  config,
+  lib,
+  modulesPath,
+  ...
+}:
+{
+  imports = [ (modulesPath + "/installer/scan/not-detected.nix") ];
+
+  boot.initrd.availableKernelModules = [
+    "xhci_pci"
+    "nvme"
+    "ahci"
+    "usbhid"
+    "sd_mod"
+  ];
+  boot.initrd.kernelModules = [ ];
+  boot.kernelModules = [ ];
+  boot.extraModulePackages = [ ];
+
+  fileSystems."/" = {
+    device = "/dev/disk/by-label/nixos";
+    fsType = "ext4";
+  };
+
+  fileSystems."/boot" = {
+    device = "/dev/disk/by-label/boot";
+    fsType = "vfat";
+  };
+
+  swapDevices = [ ];
+
+  networking.useDHCP = lib.mkDefault true;
+}