refactor: implement component-based architecture for enhanced maintainability

- Reorganize directory structure into core/, features/, and themes/
- Colocate application Nix logic, configs, scripts, and theme overrides
- Implement 'Inversion of Control' for theming: apps now pull theme-specific layouts
- Update flake.nix and shared library paths to match the new structure
- Document the new Feature-Centric architecture in README.md

features/apps/browser.nix

@@ -0,0 +1,30 @@
+{ config, pkgs, lib, ... }:
+
+let
+  nomarchyLib = import ../lib { inherit lib; };
+  activeThemeName = config.nomarchy.system.theme;
+  currentPalette = nomarchyLib.getPalette activeThemeName;
+
+  # Hex color for browser theme (base00 is background)
+  themeColor = "#${currentPalette.base00}";
+
+  # Detect light mode from theme name or palette
+  isLightTheme = nomarchyLib.isThemeLightMode {
+    themeName = activeThemeName;
+    assetsPath = ../../assets/themes;
+  };
+
+  browserPolicy = {
+    BrowserThemeColor = themeColor;
+    BrowserColorScheme = if isLightTheme then "light" else "dark";
+  };
+in
+{
+  # Chromium policies
+  programs.chromium.extraOpts = lib.mkDefault browserPolicy;
+
+  # Brave browser policies via managed policy file
+  environment.etc."brave/policies/managed/nomarchy.json".text = lib.mkDefault (
+    builtins.toJSON browserPolicy
+  );
+}