fix(nightlight): default OFF, drop wlsunset from auto-enable list

Coordinated fix with moonarch-pkgbuilds: post-install.sh enabled
wlsunset by default, while the PKGBUILD shipped a global-scope
WantedBy symlink. Together that made the toggle's user-scope disable
a no-op — filter persisted across reboots regardless of user intent.

Removing wlsunset from USER_SERVICES makes "off" the install default;
the toggle now works in user scope only, where disable can take effect.

scripts/post-install.sh

@@ -133,11 +133,13 @@ fi
 log "Enabling systemd user services..."
 USER_SERVICES=(
     "kanshi"
-    "wlsunset"
     "stasis"
     "cliphist-text"
     "cliphist-image"
 )
+# wlsunset deliberately excluded: nightlight is a user-toggle (off by default).
+# Enabling it system-wide would create a global-scope WantedBy symlink that
+# overrides any user-scope `systemctl --user disable`.
 
 for service in "${USER_SERVICES[@]}"; do
     if systemctl --user cat "${service}.service" &>/dev/null; then