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-toggle-hybrid-gpu

@@ -0,0 +1,47 @@
+#!/usr/bin/env bash
+
+# Toggle dedicated vs integrated GPU mode via supergfxd (for hybrid gpu laptops, like Asus G14).
+# Declarative enablement + Runtime mode switching for Nomarchy NixOS.
+
+STATE_FILE="/etc/nixos/state.json"
+
+# Check if supergfxd is enabled in config
+if [[ $(sudo jq -r '.features.hybridGPU // false' "$STATE_FILE") != "true" ]]; then
+    if gum confirm "Hybrid GPU support is not enabled. Enable it now? (Requires sys-update)"; then
+        sudo jq '.features.hybridGPU = true' "$STATE_FILE" > /tmp/state.json && sudo mv /tmp/state.json "$STATE_FILE"
+        echo "Hybrid GPU support enabled in configuration. Applying changes..."
+        sudo sys-update
+        echo "Please run this command again after the update."
+        exit 0
+    fi
+    exit 1
+fi
+
+if ! command -v supergfxctl &> /dev/null; then
+    echo "supergfxctl not found. Is the system updated?"
+    exit 1
+fi
+
+gpu_mode=$(supergfxctl -g)
+echo "Current GPU mode: $gpu_mode"
+
+case "$gpu_mode" in
+"Integrated")
+  if gum confirm "Switch to Hybrid mode (enables dGPU) and reboot?"; then
+    supergfxctl -m Hybrid
+    echo "Switching to Hybrid mode..."
+    nomarchy-system-reboot
+  fi
+  ;;
+"Hybrid")
+  if gum confirm "Switch to Integrated mode (disables dGPU) and reboot?"; then
+    supergfxctl -m Integrated
+    echo "Switching to Integrated mode..."
+    nomarchy-system-reboot
+  fi
+  ;;
+*)
+  echo "Hybrid GPU in unknown mode: $gpu_mode. Try 'supergfxctl -m Hybrid' manually."
+  exit 1
+  ;;
+esac