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-battery-monitor

@@ -0,0 +1,24 @@
+#!/bin/bash
+
+# Designed to be run by systemd timer every 30 seconds and alerts if battery is low
+
+BATTERY_THRESHOLD=10
+NOTIFICATION_FLAG="/run/user/$UID/nomarchy_battery_notified"
+BATTERY_LEVEL=$(nomarchy-battery-remaining)
+BATTERY_STATE=$(upower -i $(upower -e | grep 'BAT') | grep -E "state" | awk '{print $2}')
+
+send_notification() {
+  notify-send -u critical "󱐋 Time to recharge!" "Battery is down to ${1}%" -i battery-caution -t 30000
+  nomarchy-hook battery-low "$1"
+}
+
+if [[ -n $BATTERY_LEVEL && $BATTERY_LEVEL =~ ^[0-9]+$ ]]; then
+  if [[ $BATTERY_STATE == "discharging" ]] && (( BATTERY_LEVEL <= BATTERY_THRESHOLD )); then
+    if [[ ! -f $NOTIFICATION_FLAG ]]; then
+      send_notification $BATTERY_LEVEL
+      touch $NOTIFICATION_FLAG
+    fi
+  else
+    rm -f $NOTIFICATION_FLAG
+  fi
+fi