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

core/system/scripts/nomarchy-setup-dns

@@ -0,0 +1,35 @@
+#!/usr/bin/env bash
+
+# Configure DNS declaratively for Nomarchy NixOS.
+# Hybrid: updates /etc/nixos/state.json and runs sys-update.
+
+STATE_FILE="/etc/nixos/state.json"
+
+if [[ -z $1 ]]; then
+  dns=$(gum choose --height 6 --header "Select DNS provider" Cloudflare Google DHCP Custom)
+else
+  dns=$1
+fi
+
+case "$dns" in
+Cloudflare|Google|DHCP)
+  sudo jq --arg dns "$dns" '.dns = $dns' "$STATE_FILE" > /tmp/state.json && sudo mv /tmp/state.json "$STATE_FILE"
+  ;;
+
+Custom)
+  echo "Enter your DNS servers (space-separated, e.g. '192.168.1.1 1.1.1.1'):"
+  read -r dns_servers
+
+  if [[ -z $dns_servers ]]; then
+    echo "Error: No DNS servers provided."
+    exit 1
+  fi
+
+  # Convert to JSON array safely
+  dns_array=$(echo "$dns_servers" | jq -R 'split(" ")')
+  sudo jq --arg dns "Custom" --argjson servers "$dns_array" '.dns = $dns | .customDns = $servers' "$STATE_FILE" > /tmp/state.json && sudo mv /tmp/state.json "$STATE_FILE"
+  ;;
+esac
+
+echo "DNS configured to $dns. Applying changes..."
+sudo sys-update