add host skeleton modules

hosts/midgard/default.nix

@@ -1 +1,14 @@
-# TODO: Define the midgard host.
+{ ... }:
+
+{
+  # Enable these imports after collecting disk IDs and generated hardware config
+  # during the NixOS installer phase.
+  # imports = [
+  #   ./hardware-configuration.nix
+  #   ./disko.nix
+  # ];
+
+  networking.hostName = "midgard";
+
+  system.stateVersion = "25.11";
+}

hosts/midgard/disko.nix

@@ -1 +1,5 @@
-# TODO: Define the midgard disk layout.
+{ ... }:
+
+{
+  # TODO: Define the midgard disk layout.
+}

hosts/midgard/hardware-configuration.nix

@@ -1 +1,5 @@
-# TODO: Replace with generated midgard hardware configuration.
+{ ... }:
+
+{
+  # TODO: Replace with generated midgard hardware configuration.
+}