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

themes/engine/scripts/nomarchy-theme-set-vscode

@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+
+# Nomarchy VS Code Theme Setter
+# This script only updates the global state.json.
+# Home Manager (modules/home/vscode.nix) handles the declarative settings injection.
+
+STATE_DIR="$HOME/.config/nomarchy"
+STATE_FILE="$STATE_DIR/state.json"
+
+mkdir -p "$STATE_DIR"
+[[ ! -f $STATE_FILE ]] && echo "{}" > "$STATE_FILE"
+
+# Theme is already set in state.json by nomarchy-theme-set.
+# This script is now mostly a placeholder to maintain the same workflow,
+# triggering an env-update if needed to apply the declarative changes.
+
+if [[ $NOMARCHY_TOGGLE_SKIP_VSCODE_THEME != "true" ]]; then
+    # We trigger env-update to apply the new VSCode theme declaratively.
+    env-update
+fi