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/scripts/utils/nomarchy-migrate-state

@@ -0,0 +1,54 @@
+#!/usr/bin/env bash
+# Nomarchy State Migration Script
+# Migrates state from old locations to unified ~/.config/nomarchy/state.json
+
+set -e
+
+NEW_STATE_DIR="$HOME/.config/nomarchy"
+NEW_STATE_FILE="$NEW_STATE_DIR/state.json"
+OLD_HOME_STATE="$HOME/.config/home-manager/state.json"
+OLD_SYSTEM_STATE="/etc/nixos/state.json"
+
+mkdir -p "$NEW_STATE_DIR"
+
+# Initialize new state file if it doesn't exist
+if [[ ! -f "$NEW_STATE_FILE" ]]; then
+    echo "{}" > "$NEW_STATE_FILE"
+fi
+
+# Function to safely merge JSON
+merge_json() {
+    local source="$1"
+    if [[ -f "$source" ]]; then
+        echo "Migrating from $source..."
+        TMP_FILE=$(mktemp)
+        # Merge source into new state (new state values take precedence if conflict)
+        jq -s '.[0] * .[1]' "$source" "$NEW_STATE_FILE" > "$TMP_FILE" && mv "$TMP_FILE" "$NEW_STATE_FILE"
+    fi
+}
+
+# Migrate old home-manager state
+if [[ -f "$OLD_HOME_STATE" ]] && [[ "$OLD_HOME_STATE" != "$NEW_STATE_FILE" ]]; then
+    merge_json "$OLD_HOME_STATE"
+    echo "Old home state migrated. You can remove: $OLD_HOME_STATE"
+fi
+
+# Check if system state exists and user wants to sync it
+if [[ -f "$OLD_SYSTEM_STATE" ]]; then
+    echo ""
+    echo "System state found at $OLD_SYSTEM_STATE"
+    echo "Note: System state will continue to be read from /etc/nixos/state.json"
+    echo "      for system-level NixOS configuration."
+fi
+
+# Run the preflight migration for any legacy formats
+if command -v nomarchy-preflight-migration &> /dev/null; then
+    nomarchy-preflight-migration
+fi
+
+echo ""
+echo "Migration complete!"
+echo "New state location: $NEW_STATE_FILE"
+echo ""
+echo "Current state:"
+jq '.' "$NEW_STATE_FILE"