Install only the helper scripts that are still called

cpugov, sink-switcher and nightlight were referenced solely by the waybar
config; the Quickshell popouts cover all three. btnote, capsnote, vpn and
waybar-hidpp are unreferenced anywhere.

Adds the two system units for battery threshold restore and camera
shutoff, which had been missed.

hosts/testvm/default.nix

@@ -0,0 +1,38 @@
+# ABOUTME: Host configuration for the QEMU/KVM test VM.
+# ABOUTME: Launcher script lives outside this repo at ~/VMs/moonix-vm.sh.
+
+{ pkgs, ... }:
+
+{
+  imports = [ ./hardware-configuration.nix ];
+
+  boot.loader.systemd-boot.enable = true;
+  boot.loader.efi.canTouchEfiVariables = true;
+  boot.kernelParams = [ "quiet" ];
+
+  networking.hostName = "testvm";
+  networking.networkmanager.enable = true;
+
+  time.timeZone = "Europe/Berlin";
+  i18n.defaultLocale = "de_DE.UTF-8";
+  console.keyMap = "de";
+
+  users.users.kresdo = {
+    isNormalUser = true;
+    description = "Dominik Kressler";
+    extraGroups = [ "networkmanager" "wheel" "video" "input" ];
+    shell = pkgs.zsh;
+  };
+
+  # Development access from the host via the QEMU port forward on 127.0.0.1:2222.
+  services.openssh.enable = true;
+
+  # QEMU guest agent and clipboard/resolution integration.
+  services.qemuGuest.enable = true;
+  services.spice-vdagentd.enable = true;
+
+  nix.settings.experimental-features = [ "nix-command" "flakes" ];
+  nixpkgs.config.allowUnfree = true;
+
+  system.stateVersion = "26.05";
+}

hosts/testvm/hardware-configuration.nix

@@ -0,0 +1,44 @@
+# Do not modify this file!  It was generated by ‘nixos-generate-config’
+# and may be overwritten by future invocations.  Please make changes
+# to /etc/nixos/configuration.nix instead.
+{ config, lib, pkgs, modulesPath, ... }:
+
+{
+  imports =
+    [ (modulesPath + "/profiles/qemu-guest.nix")
+    ];
+
+  boot.initrd.availableKernelModules = [ "ata_piix" "virtio_pci" "floppy" "sr_mod" "virtio_blk" ];
+  boot.initrd.kernelModules = [ ];
+  boot.kernelModules = [ "kvm-amd" ];
+  boot.extraModulePackages = [ ];
+
+  fileSystems."/" =
+    { device = "/dev/disk/by-uuid/b88b75df-3999-4110-9e37-b8b76bf8206d";
+      fsType = "btrfs";
+    };
+
+  fileSystems."/home" =
+    { device = "/dev/disk/by-uuid/b88b75df-3999-4110-9e37-b8b76bf8206d";
+      fsType = "btrfs";
+      options = [ "subvol=home" ];
+    };
+
+  fileSystems."/nix" =
+    { device = "/dev/disk/by-uuid/b88b75df-3999-4110-9e37-b8b76bf8206d";
+      fsType = "btrfs";
+      options = [ "subvol=nix" ];
+    };
+
+  fileSystems."/boot" =
+    { device = "/dev/disk/by-uuid/77FC-6FE3";
+      fsType = "vfat";
+      options = [ "fmask=0077" "dmask=0077" ];
+    };
+
+  swapDevices =
+    [ { device = "/dev/disk/by-uuid/47747ffb-51b7-44c5-a2f3-6db564497c5c"; }
+    ];
+
+  nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
+}