refactor: major architectural restructure for theme-centric organization

Theme System:
- Move all theme app configs to apps/ subdirectory (20 themes)
- Add theme-loader.nix for dynamic theme config deployment
- Simplify stylix.nix to focus on base theming only

Override System:
- Add overrides.nix for file-based config overrides
- Add behavior-configs.nix for non-visual configuration
- Split hypr/nomarchy.conf into behavior vs visual sections

Module Improvements:
- Add lib.mkDefault to all customizable settings
- Add modules/lib/ with shared utilities and state schema
- Update all home and system modules for downstream overridability

Installer:
- New minimal TTY installer (installer/install.sh)
- Golden path: BTRFS + LUKS2 (disko-golden.nix)
- New installer-iso.nix for TTY-only installation
- Keep graphical installer as installerIsoGraphical option

Cleanup:
- Remove obsolete install.sh, disko-ext4.nix, install-nomarchy.sh
- Update live-iso.nix references
- Add .claude/ to .gitignore for local IDE settings

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

modules/lib/default.nix

@@ -0,0 +1,96 @@
+# Nomarchy Shared Library
+# Centralized utilities to reduce code duplication across modules
+{ lib }:
+
+let
+  # Import theme palettes once - used by multiple modules
+  palettes = import ../../assets/themes/nomarchy-palettes.nix;
+
+  # Unified state reading function
+  # Handles both JSON and plain text files with graceful fallbacks
+  readState = { file, default }:
+    if builtins.pathExists file then
+      let
+        content = builtins.readFile file;
+        cleanContent = lib.removeSuffix "\n" content;
+      in
+        if lib.hasSuffix ".json" (toString file) then
+          builtins.fromJSON cleanContent
+        else
+          cleanContent
+    else
+      default;
+
+  # Read home state from unified location
+  readHomeState = homeDirectory:
+    readState {
+      file = "${homeDirectory}/.config/nomarchy/state.json";
+      default = {};
+    };
+
+  # Read system state
+  readSystemState =
+    readState {
+      file = /etc/nixos/state.json;
+      default = {};
+    };
+
+  # Resolve wallpaper path with fallback
+  # Returns either the user-specified wallpaper or a default from the theme
+  resolveWallpaper = { wallpaperPath, themeName, assetsPath }:
+    if wallpaperPath != "" then
+      wallpaperPath
+    else
+      let
+        themeBackgrounds = assetsPath + "/${themeName}/backgrounds";
+        defaultBackground = assetsPath + "/catppuccin/backgrounds/1-totoro.png";
+      in
+        if builtins.pathExists themeBackgrounds then
+          let
+            backgrounds = builtins.attrNames (builtins.readDir themeBackgrounds);
+          in
+            if backgrounds != [] then
+              "${themeBackgrounds}/${builtins.head (builtins.sort (a: b: a < b) backgrounds)}"
+            else
+              defaultBackground
+        else
+          defaultBackground;
+
+  # Get current palette from theme name
+  getPalette = themeName:
+    (palettes.${themeName} or palettes.nord).palette;
+
+  # Get full color scheme from theme name
+  getColorScheme = themeName:
+    palettes.${themeName} or palettes.nord;
+
+  # Check if a theme is light mode
+  isThemeLightMode = { themeName, assetsPath }:
+    builtins.pathExists (assetsPath + "/${themeName}/light.mode");
+
+  # Get icons theme for a given theme
+  getIconsTheme = { themeName, assetsPath, default ? "Yaru-blue" }:
+    let
+      iconsFile = assetsPath + "/${themeName}/icons.theme";
+    in
+      if builtins.pathExists iconsFile then
+        lib.removeSuffix "\n" (builtins.readFile iconsFile)
+      else
+        default;
+
+  # Get list of available theme names
+  themeNames = builtins.attrNames palettes;
+
+in {
+  inherit
+    palettes
+    readState
+    readHomeState
+    readSystemState
+    resolveWallpaper
+    getPalette
+    getColorScheme
+    isThemeLightMode
+    getIconsTheme
+    themeNames;
+}

modules/lib/state-schema.nix

@@ -0,0 +1,66 @@
+# Nomarchy State Schema
+# Defines the complete state shape with defaults for both home and system state
+{ lib }:
+
+{
+  # Home state defaults (user preferences)
+  home = {
+    # Theme and appearance
+    theme = "nord";
+    wallpaper = "";
+    font = "JetBrainsMono Nerd Font";
+    nightlightTemperature = 4000;
+
+    # Feature toggles
+    suspend = true;
+    screensaver = true;
+    idle = true;
+    nightlight = false;
+    waybar = true;
+    skipVsCodeTheme = false;
+
+    # Hyprland window manager settings
+    hyprland = {
+      gaps_in = 5;
+      gaps_out = 10;
+      border_size = 2;
+    };
+  };
+
+  # System state defaults (system-level configuration)
+  system = {
+    # Theme (can differ from home for system-level theming)
+    theme = "nord";
+
+    # Timezone
+    timezone = "UTC";
+
+    # DNS configuration
+    dns = "DHCP";  # Options: "DHCP", "Cloudflare", "Google", "Custom"
+    customDns = [];
+
+    # Wi-Fi settings
+    wifi = {
+      powersave = true;
+    };
+
+    # Optional features
+    features = {
+      fingerprint = false;
+      fido2 = false;
+      hybridGPU = false;
+      makima = false;
+    };
+  };
+
+  # Get a value from state with fallback to default
+  getWithDefault = state: path: default:
+    let
+      pathList = lib.splitString "." path;
+      getValue = obj: remaining:
+        if remaining == [] then obj
+        else if builtins.isAttrs obj && builtins.hasAttr (builtins.head remaining) obj
+        then getValue obj.${builtins.head remaining} (builtins.tail remaining)
+        else default;
+    in getValue state pathList;
+}