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/home/hyprland.nix

@@ -1,20 +1,27 @@
 { config, pkgs, lib, ... }:
 
 let
-  activeWallpaper = if config.nomarchy.wallpaper != "" then 
-    config.nomarchy.wallpaper 
-  else "${../../assets/themes/catppuccin/backgrounds/1-totoro.png}";
+  nomarchyLib = import ../lib { inherit lib; };
+  assetsPath = ../../assets/themes;
+
+  # Use shared wallpaper resolver
+  activeWallpaper = nomarchyLib.resolveWallpaper {
+    wallpaperPath = config.nomarchy.wallpaper;
+    themeName = config.nomarchy.theme;
+    inherit assetsPath;
+  };
+
   hyprlandState = config.nomarchy.hyprland;
 in
 {
-  home.sessionVariables = {
+  home.sessionVariables = lib.mkDefault {
     WLR_NO_HARDWARE_CURSORS = "1";
     HYPRLAND_LOG_WLR = "1";
   };
 
   wayland.windowManager.hyprland = {
-    enable = true;
-    settings = {
+    enable = lib.mkDefault true;
+    settings = lib.mkDefault {
       "debug" = {
         "disable_logs" = false;
         "enable_stdout_logs" = true;
@@ -30,7 +37,7 @@ in
         "col.inactive_border" = "rgb(${config.colorScheme.palette.base03})";
       };
     };
-    extraConfig = ''
+    extraConfig = lib.mkDefault ''
       source = ~/.config/hypr/nomarchy.conf
     '';
   };