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/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;
+  };
+}