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/waybar.nix

@@ -0,0 +1,155 @@
+# Waybar — two-tier theming:
+#
+#  1. Default: structure, fonts, geometry AND palette baked from
+#     theme-state.json (colors as GTK named colors, @define-color).
+#
+#  2. Whole-swap: themes with their own visual identity ship
+#     <themesDir>/<slug>/waybar.css (and optionally waybar.jsonc) which
+#     replace the generated style/layout entirely. Probed at eval time —
+#     pure, it's flake source.
+{ config, lib, ... }:
+
+let
+  t = config.nomarchy.theme;
+
+  # Per-theme override probe.
+  assetDir = config.nomarchy.themesDir + "/${t.slug}";
+  styleOverride = assetDir + "/waybar.css";
+  configOverride = assetDir + "/waybar.jsonc";
+  hasStyleOverride = builtins.pathExists styleOverride;
+  hasConfigOverride = builtins.pathExists configOverride;
+
+  # The palette as GTK named colors, straight from the JSON.
+  colorDefs = lib.concatStringsSep "\n"
+    (lib.mapAttrsToList (name: value: "@define-color ${name} ${value};") t.colors);
+
+  generatedSettings = {
+    layer = "top";
+    position = "top";
+    height = 34;
+    margin-top = t.ui.gapsOut;
+    margin-left = t.ui.gapsOut;
+    margin-right = t.ui.gapsOut;
+    spacing = 8;
+
+    # waybar re-reads style.css when it changes on disk, so a
+    # home-manager switch restyles the running bar without a restart.
+    reload_style_on_change = true;
+
+    modules-left = [ "hyprland/workspaces" "hyprland/window" ];
+    modules-center = [ "clock" ];
+    modules-right = [ "tray" "pulseaudio" "network" "cpu" "memory" "battery" ];
+
+    "hyprland/workspaces" = {
+      format = "{icon}";
+      on-click = "activate";
+    };
+
+    "hyprland/window" = {
+      max-length = 48;
+      separate-outputs = true;
+    };
+
+    clock = {
+      format = "{:%H:%M}";
+      format-alt = "{:%A %d %B %Y}";
+      tooltip-format = "<tt><small>{calendar}</small></tt>";
+    };
+
+    pulseaudio = {
+      format = "{icon} {volume}%";
+      format-muted = "󰝟";
+      format-icons.default = [ "󰕿" "󰖀" "󰕾" ];
+      on-click = "pamixer -t";
+    };
+
+    network = {
+      format-wifi = "󰤨 {essid}";
+      format-ethernet = "󰈀";
+      format-disconnected = "󰤭";
+      tooltip-format = "{ipaddr} via {gwaddr}";
+    };
+
+    cpu.format = "󰍛 {usage}%";
+    memory.format = "󰾆 {percentage}%";
+
+    battery = {
+      states = { warning = 25; critical = 10; };
+      format = "{icon} {capacity}%";
+      format-charging = "󰂄 {capacity}%";
+      format-icons = [ "󰁺" "󰁼" "󰁾" "󰂀" "󰁹" ];
+    };
+
+    tray.spacing = 8;
+  };
+
+  generatedStyle = ''
+    /* Palette baked from theme-state.json */
+    ${colorDefs}
+
+    * {
+      font-family: "${t.fonts.ui}", "${t.fonts.mono}";
+      font-size: ${toString t.fonts.size}pt;
+      min-height: 0;
+    }
+
+    window#waybar {
+      background: alpha(@base, 0.85);
+      color: @text;
+      border: ${toString t.ui.borderSize}px solid alpha(@accent, 0.4);
+      border-radius: ${toString t.ui.rounding}px;
+    }
+
+    #workspaces button {
+      padding: 0 8px;
+      color: @muted;
+      border-radius: ${toString t.ui.rounding}px;
+    }
+
+    #workspaces button.active {
+      color: @base;
+      background: @accent;
+    }
+
+    #workspaces button.urgent {
+      color: @base;
+      background: @bad;
+    }
+
+    #window {
+      color: @subtext;
+      padding: 0 12px;
+    }
+
+    #clock {
+      color: @text;
+      font-weight: bold;
+    }
+
+    #tray, #pulseaudio, #network, #cpu, #memory, #battery {
+      color: @subtext;
+      padding: 0 10px;
+    }
+
+    #pulseaudio.muted { color: @muted; }
+    #battery.warning { color: @warn; }
+    #battery.critical { color: @bad; }
+    #battery.charging { color: @good; }
+  '';
+in
+{
+  programs.waybar = lib.mkIf config.nomarchy.waybar.enable {
+    enable = true;
+    systemd.enable = true; # started/stopped with graphical-session.target
+
+    settings.mainBar =
+      if hasConfigOverride
+      then builtins.fromJSON (builtins.readFile configOverride)
+      else generatedSettings;
+
+    style =
+      if hasStyleOverride
+      then builtins.readFile styleOverride
+      else generatedStyle;
+  };
+}