Restructure into a multi-machine flake and add the enzo laptop

Split the single-host config into a shared minimal base plus opt-in
profiles, and add a second machine (enzo laptop) alongside kusanagi.

- flake: add mkMachine helper; declare nixosConfigurations.kusanagi and
  .enzo; add the disko input; move overlays per-machine.
- common/: minimal base only (boot, networking, tailscale, locale, nix
  settings, neovim editor). Old configuration.nix/programs.nix removed.
- profiles/: coarse opt-in bundles (desktop, dev, apps). kusanagi imports
  all three and stays byte-for-byte identical to the running system.
- machines/kusanagi/: all workstation-only config (ROCm, Scarlett audio,
  optical-disc archiving, NAS mounts, kavita/immich/ollama); hardware
  config moved here unchanged. User stays 'henz'.
- machines/enzo/: new laptop. Declarative LUKS+btrfs via disko
  (LVM-on-LUKS, TPM2+PIN unlock, zram + encrypted swap for
  suspend-then-hibernate); its own minimal niri desktop with
  playback-only audio (no rtkit/jack); user 'hwebs'.

Assisted-by: Claude:claude-opus-4-8

1 files changed, 27 insertions, 0 deletions

diff --git a/machines/enzo/hardware-configuration.nix b/machines/enzo/hardware-configuration.nix
new file mode 100644
index 0000000..30c00ee
--- /dev/null
+++ b/machines/enzo/hardware-configuration.nix
@@ -0,0 +1,27 @@
+# PLACEHOLDER — regenerate on the laptop.
+#
+# During install run:  nixos-generate-config --no-filesystems --root /mnt
+# then copy the generated hardware-configuration.nix over this file. Because the
+# disk layout is declared in ./disko.nix, this file must NOT define fileSystems
+# or swapDevices (--no-filesystems omits them). It only needs to evaluate until
+# the real one is generated; it will NOT boot as-is.
+{ config, lib, pkgs, modulesPath, ... }:
+
+{
+  imports = [
+    (modulesPath + "/installer/scan/not-detected.nix")
+  ];
+
+  # nixos-generate-config fills these in on the laptop. TPM unlock in initrd
+  # needs the TPM module (tpm_tis / tpm_crb) here — usually auto-detected.
+  boot.initrd.availableKernelModules = [ ];
+  boot.initrd.kernelModules = [ ];
+  boot.kernelModules = [ ];
+  boot.extraModulePackages = [ ];
+
+  # fileSystems / swapDevices intentionally omitted — provided by ./disko.nix.
+
+  networking.useDHCP = lib.mkDefault true;
+
+  nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
+}