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-status

@@ -0,0 +1,28 @@
+#!/bin/bash
+
+# Returns a formatted battery status string with percentage and power draw/charge.
+# Used by the battery notification hotkey (Ctrl + Shift + Super + B).
+
+battery_info=$(upower -i $(upower -e | grep BAT))
+
+percentage=$(echo "$battery_info" | awk '/percentage/ {
+    print int($2)
+    exit
+}')
+
+power_rate=$(echo "$battery_info" | awk '/energy-rate/ {
+    rounded = sprintf("%.1f", $2)
+    sub(/\.0$/, "", rounded)
+    print rounded
+    exit
+}')
+
+state=$(echo "$battery_info" | awk '/state/ { print $2; exit }')
+time_remaining=$(nomarchy-battery-remaining-time)
+capacity=$(nomarchy-battery-capacity)
+
+if [[ $state == "charging" ]]; then
+    echo "󰁹    Battery ${percentage}%  ·  ${time_remaining} to full  ·   ${power_rate}W / ${capacity}Wh"
+else
+    echo "󰁹    Battery ${percentage}%  ·  ${time_remaining} left  ·   ${power_rate}W / ${capacity}Wh"
+fi