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/stylix.nix

@@ -0,0 +1,79 @@
+# Stylix — themes the long tail of applications (GTK, Qt, cursors,
+# fonts) from the same theme-state.json that drives the live engine.
+#
+# Division of labour: the hot-reload trio (Hyprland, Waybar, Ghostty)
+# is owned by the Nomarchy engine and updates instantly; everything
+# Stylix touches updates on the next home-manager switch. That is why
+# autoEnable is off and the trio's Stylix targets stay disabled.
+#
+# Note: the stylix home module itself is imported by homeModules.nomarchy
+# in flake.nix (it needs the stylix flake input).
+{ config, lib, pkgs, ... }:
+
+let
+  cfg = config.nomarchy;
+  t = cfg.theme;
+  c = t.colors;
+  hex = lib.removePrefix "#";
+
+  # Map the Nomarchy palette onto base16 roles.
+  base16 = {
+    base00 = hex c.base;     # default background
+    base01 = hex c.mantle;   # darker background (status bars)
+    base02 = hex c.surface;  # selection background
+    base03 = hex c.muted;    # comments
+    base04 = hex c.subtext;  # dark foreground
+    base05 = hex c.text;     # default foreground
+    base06 = hex c.text;     # light foreground
+    base07 = hex c.text;     # lightest foreground
+    base08 = hex c.bad;      # red
+    base09 = hex c.warn;     # orange
+    base0A = hex c.warn;     # yellow
+    base0B = hex c.good;     # green
+    base0C = hex (builtins.elemAt t.ansi 6); # cyan
+    base0D = hex c.accent;   # blue
+    base0E = hex c.accentAlt;# magenta
+    base0F = hex c.bad;      # brown/deprecated
+  };
+in
+{
+  config = lib.mkIf cfg.stylix.enable {
+    stylix = {
+      enable = true;
+      autoEnable = false; # explicit targets only — the engine owns the rest
+      polarity = if t.mode == "light" then "light" else "dark";
+      base16Scheme = base16;
+
+      targets = {
+        gtk.enable = true;
+        qt.enable = true;
+      };
+
+      cursor = {
+        name = lib.mkDefault "Bibata-Modern-Classic";
+        package = lib.mkDefault pkgs.bibata-cursors;
+        size = lib.mkDefault 24;
+      };
+
+      fonts = {
+        monospace = {
+          name = t.fonts.mono;
+          package = lib.mkDefault pkgs.nerd-fonts.jetbrains-mono;
+        };
+        sansSerif = {
+          name = t.fonts.ui;
+          package = lib.mkDefault pkgs.inter;
+        };
+        serif = {
+          name = t.fonts.ui;
+          package = lib.mkDefault pkgs.inter;
+        };
+        emoji = {
+          name = "Noto Color Emoji";
+          package = lib.mkDefault pkgs.noto-fonts-color-emoji;
+        };
+        sizes.terminal = t.fonts.size;
+      };
+    };
+  };
+}