feat: Nomarchy ground-up rewrite on NixOS 26.05

Full replacement of the previous iteration, rebuilt around three ideas:

- Pure evaluation: theme-state.json lives inside the flake and is read
  via the nomarchy.stateFile option — no --impure, ever.
- All-Home-Manager theming: `nomarchy-theme-sync apply` writes the JSON
  and runs `home-manager switch`; every theme change is one atomic,
  rollbackable generation. Wallpaper (swww) is the sole runtime piece.
- Flat, downstream-first layout: modules/{nixos,home} with one
  options.nix each, exported as nixosModules/homeModules + overlay +
  flake template; system (nixos-rebuild) and desktop (home-manager
  switch) rebuild paths are fully split.

Ships 21 themes imported from the previous iteration (palettes,
wallpapers, btop themes, six whole-swap Waybar identities), Stylix for
the GTK/Qt/cursor long tail, a live ISO target with offline theme
switching, and docs/TESTING.md with the QEMU verification workflow.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

modules/nixos/default.nix

@@ -0,0 +1,100 @@
+# Nomarchy — reusable system layer (NixOS 26.05).
+#
+# This module is the distro: import it from any host (see
+# nixosModules.nomarchy in flake.nix) and layer your machine specifics
+# (bootloader, hostname, users, hardware) on top. Host concerns are
+# deliberately NOT set here. Everything user-facing (Hyprland config,
+# Waybar, Ghostty, theming) lives in modules/home.
+{ config, lib, pkgs, ... }:
+
+let
+  cfg = config.nomarchy.system;
+in
+{
+  imports = [ ./options.nix ];
+
+  config = {
+    # ── Wayland session: Hyprland ────────────────────────────────────
+    # Installs the binary, registers the session, wires up
+    # xdg-desktop-portal-hyprland. Configuration is Home Manager's job.
+    programs.hyprland.enable = lib.mkDefault true;
+
+    xdg.portal = {
+      enable = lib.mkDefault true;
+      extraPortals = [ pkgs.xdg-desktop-portal-gtk ]; # file pickers, etc.
+    };
+
+    services.greetd = lib.mkIf cfg.greeter.enable {
+      enable = lib.mkDefault true;
+      settings.default_session = {
+        command = lib.mkDefault "${pkgs.greetd.tuigreet}/bin/tuigreet --time --remember --cmd Hyprland";
+        user = "greeter";
+      };
+    };
+
+    # ── Audio: Pipewire ──────────────────────────────────────────────
+    security.rtkit.enable = lib.mkDefault cfg.audio.enable;
+    services.pulseaudio.enable = lib.mkDefault false;
+    services.pipewire = lib.mkIf cfg.audio.enable {
+      enable = lib.mkDefault true;
+      alsa.enable = true;
+      alsa.support32Bit = true;
+      pulse.enable = true;
+      wireplumber.enable = true;
+    };
+
+    # ── Desktop services ─────────────────────────────────────────────
+    security.polkit.enable = lib.mkDefault true;
+    services.gnome.gnome-keyring.enable = lib.mkDefault true;
+    services.dbus.enable = lib.mkDefault true;
+    services.upower.enable = lib.mkDefault true;
+    networking.networkmanager.enable = lib.mkDefault true;
+
+    hardware.bluetooth.enable = lib.mkDefault cfg.bluetooth.enable;
+    services.blueman.enable = lib.mkDefault cfg.bluetooth.enable;
+
+    # ── Fonts ────────────────────────────────────────────────────────
+    fonts = {
+      packages = with pkgs; [
+        nerd-fonts.jetbrains-mono
+        inter
+        noto-fonts
+        noto-fonts-color-emoji
+      ];
+      fontconfig.defaultFonts = {
+        monospace = lib.mkDefault [ "JetBrainsMono Nerd Font" ];
+        sansSerif = lib.mkDefault [ "Inter" ];
+        emoji = lib.mkDefault [ "Noto Color Emoji" ];
+      };
+    };
+
+    # ── Essential packages ───────────────────────────────────────────
+    environment.systemPackages = with pkgs; [
+      nomarchy-theme-sync # provided by overlays.default
+      git
+      vim
+      wget
+      curl
+      jq
+      brightnessctl
+      playerctl
+      pamixer
+      wl-clipboard
+      grim
+      slurp
+    ];
+
+    # ── Nix itself ───────────────────────────────────────────────────
+    nix = {
+      settings = {
+        experimental-features = [ "nix-command" "flakes" ];
+        auto-optimise-store = lib.mkDefault true;
+      };
+      gc = {
+        automatic = lib.mkDefault true;
+        dates = lib.mkDefault "weekly";
+        options = lib.mkDefault "--delete-older-than 14d";
+      };
+    };
+  };
+}

modules/nixos/options.nix

@@ -0,0 +1,14 @@
+# System-level `nomarchy.system.*` options.
+#
+# Deliberately small: only things a downstream user plausibly disagrees
+# with get a toggle. Everything else in the system module is set with
+# lib.mkDefault, so plain NixOS options override it natively.
+{ lib, ... }:
+
+{
+  options.nomarchy.system = {
+    greeter.enable = lib.mkEnableOption "the greetd/tuigreet login screen" // { default = true; };
+    audio.enable = lib.mkEnableOption "the Pipewire audio stack" // { default = true; };
+    bluetooth.enable = lib.mkEnableOption "Bluetooth support with blueman" // { default = true; };
+  };
+}