feat: make VM and live ISO match an installed Nomarchy

- Migrate VM and graphical ISO to home-manager.nixosModules.home-manager;
  drop the standalone-HM sudo-based activation script (ran HM against
  /root because HOME wasn't reset) in flake.nix, core/system/vm-guest.nix,
  hosts/live-iso.nix.
- Run swaybg as nomarchy-wallpaper.service instead of a silent Hyprland
  exec-once so failures surface in systemctl.
- Skip the battery monitor unit on hosts without /sys/class/power_supply/BAT*
  (VMs, desktops).
- Don't wrap walker --dmenu in uwsm-app; redirect setsid background std-fds
  in nomarchy-launch-walker so $(menu ...) in nomarchy-menu doesn't hang.
- Restart waybar/walker via systemctl --user rather than pkill + uwsm-app
  to stop the post-theme-switch color race.
- Wire nomarchy-restart-walker/-waybar into nomarchy-theme-set so themes
  that only change the imported CSS reload correctly.
- Waybar: pin #custom-nomarchy to the Nomarchy font and use the U+F000
  codepoint so the logo shows across all themes.
- Auto-install the correct icon-theme package per palette via a new
  nomarchyLib.iconThemePackage helper in lib/default.nix; Everforest now
  actually renders for summer-night.
- Pre-cache every theme's HM generation: new packages.allThemeVariants
  flake output and nomarchy-themes-prebuild script so theme switches are
  cache-only (no Stylix rebuild, no downloads).
- Add nomarchy-test-live-iso to boot the graphical ISO in QEMU the same
  way nomarchy-test-vm does, with virtio-gpu support added to live-iso.nix.
- Installer-generated home.nix/system.nix now ship a curated, commented
  app menu (btop/fastfetch/chromium on by default) plus optional system
  services (Docker, libvirtd, Tailscale, Syncthing, Flatpak, Steam).
- nomarchy-test-vm now wipes the stale nomarchy.qcow2 before launch.
- Remove obsolete GEMINI.md and PLAN.md.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

lib/default.nix

@@ -78,6 +78,20 @@ let
       else
         default;
 
+  # Map an icon-theme name (as declared in a palette's icons.theme file) to
+  # the nixpkgs attribute that ships it. Anything unknown falls back to
+  # yaru-theme so GTK still has a working default.
+  #
+  # When adding a palette that uses a new icon family, extend this mapping
+  # so `nomarchy-theme-set <name>` auto-installs the matching package.
+  iconThemePackage = { iconsTheme, pkgs }:
+    if lib.hasPrefix "Yaru" iconsTheme then pkgs.yaru-theme
+    else if lib.hasPrefix "Everforest" iconsTheme then pkgs.everforest-gtk-theme
+    else if lib.hasPrefix "Papirus" iconsTheme then pkgs.papirus-icon-theme
+    else if lib.hasPrefix "Adwaita" iconsTheme then pkgs.adwaita-icon-theme
+    else if lib.hasPrefix "breeze" iconsTheme || lib.hasPrefix "Breeze" iconsTheme then pkgs.kdePackages.breeze-icons
+    else pkgs.yaru-theme;
+
   # Get list of available theme names
   themeNames = builtins.attrNames palettes;
 
@@ -92,5 +106,6 @@ in {
     getColorScheme
     isThemeLightMode
     getIconsTheme
+    iconThemePackage
     themeNames;
 }