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>

hosts/live.nix

@@ -0,0 +1,85 @@
+# Live ISO host — boot the full Nomarchy desktop from a USB stick or QEMU
+# without touching the disk. No installer yet (see roadmap); this target
+# exists to test the distro end-to-end on real hardware.
+{ lib, pkgs, username, nomarchySrc, ... }:
+
+{
+  networking.hostName = "nomarchy-live";
+
+  isoImage.volumeID = lib.mkForce "NOMARCHY_LIVE";
+  isoImage.edition = lib.mkForce "live";
+
+  # The minimal-CD profile enables wpa_supplicant; Nomarchy ships
+  # NetworkManager and the two must not run together.
+  networking.wireless.enable = lib.mkForce false;
+
+  # ── Live user: no password, straight into the desktop ──────────────
+  users.users.${username} = {
+    isNormalUser = true;
+    initialHashedPassword = "";
+    extraGroups = [ "wheel" "networkmanager" "video" "render" "audio" "input" ];
+  };
+  security.sudo.wheelNeedsPassword = false;
+  services.getty.autologinUser = lib.mkForce username;
+
+  # Boot straight into Hyprland once; logging out lands on tuigreet.
+  services.greetd.settings.initial_session = {
+    command = "Hyprland";
+    user = username;
+  };
+
+  # ── Hardware breadth ────────────────────────────────────────────────
+  # Force-loading every GPU driver in the initrd (amdgpu+radeon+nouveau+
+  # i915) panics most machines — only one of them can claim the GPU and
+  # the others explode. `availableKernelModules` lets udev load just the
+  # one that matches; virtio_gpu covers QEMU (tools/test-live-iso.sh).
+  boot.initrd.availableKernelModules = [ "amdgpu" "radeon" "nouveau" "i915" "virtio_gpu" ];
+  services.qemuGuest.enable = lib.mkDefault true;
+
+  # ── The Nomarchy flake on board ─────────────────────────────────────
+  # Read-only copy in /etc (also pins the flake source into the ISO
+  # closure); seeded writable into the live home so theme switching —
+  # state write + `home-manager switch` — works exactly like on an
+  # installed system. $NOMARCHY_PATH already defaults to ~/.nomarchy.
+  environment.etc."nomarchy".source = nomarchySrc;
+
+  systemd.services.nomarchy-seed-flake = {
+    description = "Seed a writable Nomarchy flake into the live user's home";
+    wantedBy = [ "multi-user.target" ];
+    serviceConfig.Type = "oneshot";
+    script = ''
+      home=/home/${username}
+      if [ ! -e "$home/.nomarchy" ]; then
+        cp -r ${nomarchySrc} "$home/.nomarchy"
+        chmod -R u+w "$home/.nomarchy"
+        chown -R ${username}:users "$home/.nomarchy"
+      fi
+    '';
+  };
+
+  services.getty.helpLine = lib.mkForce ''
+
+    Welcome to the Nomarchy live environment.
+
+    The graphical session autologins as '${username}' (no password).
+    Theme switching:  nomarchy-theme-sync apply <name>   (or SUPER+T)
+    Wallpapers:       nomarchy-theme-sync bg next        (or SUPER+SHIFT+T)
+    The flake lives at ~/.nomarchy.
+  '';
+
+  # ── Live-session desktop tweaks ─────────────────────────────────────
+  home-manager.users.${username} = {
+    wayland.windowManager.hyprland.settings = {
+      # QEMU (and some panels) report a tiny "preferred" mode; ask for
+      # the highest resolution instead.
+      monitor = lib.mkForce [ ",highres,auto,1" ];
+      # Welcome toast once the session is up (concatenated onto the
+      # base exec-once list).
+      exec-once = [
+        "sh -c 'sleep 3; notify-send -a Nomarchy \"Welcome to Nomarchy\" \"SUPER+Return terminal · SUPER+T themes · SUPER+SHIFT+T wallpaper\"'"
+      ];
+    };
+  };
+
+  system.stateVersion = "26.05";
+}