Add shutdown check to power button hotplug script

packages/router-display/files/hotplugs/30_power_update

@@ -1,10 +1,19 @@
 #!/bin/sh
+# /etc/hotplug.d/button/30_power_update
 
 # Only process power button events
 [ "$BUTTON" = "power" ] || exit 0
 
 # Execute update-display on button release
 [ "${ACTION}" = "released" ] && {
+    # Check if system is shutting down
+    if pgrep poweroff >/dev/null 2>&1 || \
+       pgrep halt >/dev/null 2>&1 || \
+       pgrep reboot >/dev/null 2>&1; then
+        logger -t display "System shutting down - skipping update-display"
+        exit 0
+    fi
+    
     /usr/sbin/update-display
 }