Add powermenu script and apply Tomorrow Night color theme

- Add scripts/powermenu.sh with logout, restart, sleep, shutdown options
- Create wofi/style.css with Tomorrow Night colors
- Apply Tomorrow Night theme to niri, waybar, mako, alacritty, and wofi

scripts/powermenu.sh

@@ -0,0 +1,18 @@
+#!/bin/bash
+
+CHOICE=$(printf "  Logout\n  Restart\n  Sleep\n  Shutdown" \
+    | wofi --dmenu \
+           --prompt "Power:" \
+           --width 300 \
+           --height 220 \
+           --hide-scroll \
+           --no-actions \
+           --insensitive \
+    | awk '{print $2}')
+
+case "$CHOICE" in
+    Logout)   niri msg action quit ;;
+    Restart)  systemctl reboot ;;
+    Sleep)    systemctl suspend ;;
+    Shutdown) systemctl poweroff ;;
+esac