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/home/options.nix

@@ -0,0 +1,64 @@
+# User-level `nomarchy.*` options — the full surface downstream users
+# configure in their home.nix. Kept small on purpose.
+{ lib, pkgs, ... }:
+
+{
+  options.nomarchy = {
+    # ── Required ───────────────────────────────────────────────────
+    stateFile = lib.mkOption {
+      type = lib.types.path;
+      example = lib.literalExpression "./theme-state.json";
+      description = ''
+        Path to theme-state.json, the single source of truth for all UI
+        configuration. Must live inside your flake (so evaluation stays
+        pure) and be git-tracked. nomarchy-theme-sync writes to the
+        on-disk copy; rebuilds bake it into the generation.
+      '';
+    };
+
+    # ── Preferences ────────────────────────────────────────────────
+    terminal = lib.mkOption {
+      type = lib.types.str;
+      default = "ghostty";
+      description = "Terminal emulator command, used by keybinds and $TERMINAL.";
+    };
+
+    package = lib.mkOption {
+      type = lib.types.package;
+      default = pkgs.nomarchy-theme-sync;
+      defaultText = lib.literalExpression "pkgs.nomarchy-theme-sync";
+      description = "The nomarchy-theme-sync package (provided by overlays.default).";
+    };
+
+    themesDir = lib.mkOption {
+      type = lib.types.path;
+      default = ../../themes;
+      defaultText = lib.literalExpression "\"\${nomarchy}/themes\"";
+      description = ''
+        Theme presets/assets directory probed at eval time for per-theme
+        app overrides (<slug>/waybar.css, <slug>/waybar.jsonc). Point it
+        at your own directory to ship custom layouts downstream.
+      '';
+    };
+
+    # ── Component toggles ──────────────────────────────────────────
+    hyprland.enable = lib.mkEnableOption "Nomarchy's Hyprland configuration" // { default = true; };
+    waybar.enable = lib.mkEnableOption "Nomarchy's Waybar configuration" // { default = true; };
+    ghostty.enable = lib.mkEnableOption "Nomarchy's Ghostty configuration" // { default = true; };
+    btop.enable = lib.mkEnableOption "btop with the per-theme nomarchy theme" // { default = true; };
+    stylix.enable = lib.mkEnableOption "Stylix theming for the long tail of apps (GTK, Qt, cursors)" // { default = true; };
+
+    # ── Computed (read-only) ───────────────────────────────────────
+    theme = lib.mkOption {
+      type = lib.types.attrs;
+      readOnly = true;
+      description = "The parsed theme state (stateFile merged over defaults).";
+    };
+
+    lib = lib.mkOption {
+      type = lib.types.attrs;
+      readOnly = true;
+      description = "Color-format helpers shared by the theme consumers.";
+    };
+  };
+}