fix(waybar): show the battery widget on the default summer-night theme

The summer-night waybar config defined a custom/battery module
(exec nomarchy-battery-status) but never listed it in any modules-*
slot, so it was orphaned and never rendered. summer-night is the
default theme, so a laptop on a stock install had no battery
indicator — the default fallback config and the summer-day theme
both place battery in modules-right; only summer-night omitted it.

Add custom/battery to summer-night's modules-right. The formFactor
filter (laptopOnlyModules) already lists custom/battery, so it shows
on laptop and is dropped on desktop. Found during the Pillar 9
Component 9 (form-factor split) verification pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

features/desktop/waybar/themes/summer-night/config.jsonc

@@ -9,7 +9,7 @@
   "spacing": 15,
   "modules-left": ["custom/nomarchy", "clock", "clock#date"],
   "modules-center": ["hyprland/workspaces"],
-  "modules-right": [ "idle_inhibitor", "pulseaudio", "tray", "custom/powermenu"],
+  "modules-right": [ "idle_inhibitor", "pulseaudio", "custom/battery", "tray", "custom/powermenu"],
 
   "hyprland/workspaces": {
       "disable-scroll": true,