Split shared host config into dedicated modules

- Add shared modules for boot, hardware, networking, input, and host defaults
- Move host-specific TOML flags to new option namespaces
- Update SSH and service defaults for the new layout

modules/nixos/shared/hardware/default.nix

@@ -1,5 +1,7 @@
 {
   imports = [
     ./facter.nix
+    ./graphics/vaapi.nix
+    ./power-save.nix
   ];
 }

modules/nixos/shared/hardware/graphics/vaapi.nix

@@ -0,0 +1,29 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}: let
+  inherit (lib) mkIf mkOption types;
+  cfg = config.unexplrd.hardware.graphics.vaapi;
+in {
+  options.unexplrd.hardware.graphics.vaapi = mkOption {
+    type = types.nullOr (types.enum ["intel-media-driver" "nvidia"]);
+    default = null;
+  };
+
+  config = lib.mkMerge [
+    (mkIf (cfg == "intel-media-driver") {
+      hardware.graphics.extraPackages = with pkgs; [
+        intel-compute-runtime
+        intel-media-driver
+        vpl-gpu-rt
+      ];
+    })
+    (mkIf (cfg == "nvidia") {
+      hardware.graphics.extraPackages = with pkgs; [
+        nvidia-vaapi-driver
+      ];
+    })
+  ];
+}

modules/nixos/shared/hardware/power-save.nix

@@ -0,0 +1,20 @@
+{
+  config,
+  lib,
+  ...
+}: let
+  inherit (lib) mkEnableOption mkIf;
+  cfg = config.unexplrd.hardware.powerSave;
+in {
+  options.unexplrd.hardware.powerSave.enable =
+    mkEnableOption "power saving defaults";
+
+  config = mkIf cfg.enable {
+    powerManagement.enable = true;
+    powerManagement.powertop.enable = true;
+    services.power-profiles-daemon.enable = true;
+    services.thermald.enable = true;
+    services.upower.enable = true;
+    hardware.bluetooth.settings.Policy.AutoEnable = false;
+  };
+}