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/ghostty.nix

@@ -0,0 +1,41 @@
+# Ghostty — Nomarchy's default terminal, themed from theme-state.json.
+# Colors, fonts and the full 16-color ANSI palette are baked from the
+# JSON at eval time.
+{ config, lib, ... }:
+
+let
+  t = config.nomarchy.theme;
+  c = t.colors;
+in
+{
+  programs.ghostty = lib.mkIf config.nomarchy.ghostty.enable {
+    enable = true;
+    enableBashIntegration = true;
+
+    settings = {
+      # ── Typography (from theme-state.json) ────────────────────────
+      font-family = t.fonts.mono;
+      font-size = t.fonts.size;
+
+      # ── Colors (from theme-state.json) ────────────────────────────
+      background = c.base;
+      foreground = c.text;
+      cursor-color = c.accent;
+      selection-background = c.overlay;
+      selection-foreground = c.text;
+      split-divider-color = c.surface;
+
+      # "N=#rrggbb" entries; Ghostty accepts repeated `palette` keys,
+      # which the HM module renders from this list.
+      palette = lib.imap0 (i: color: "${toString i}=${color}") t.ansi;
+
+      # ── Chrome ────────────────────────────────────────────────────
+      background-opacity = t.ui.terminalOpacity;
+      window-padding-x = 12;
+      window-padding-y = 12;
+      window-decoration = false;
+      gtk-single-instance = true;
+      confirm-close-surface = false;
+    };
+  };
+}