Don't fire a pending idle action whose timeout was set to 0

The timers' intervals are bound to the configured delays, so setting the lock or screensaver to 0 while the screensaver is up turns a pending timer's interval to 0 and it fires at once. Check the action is still enabled when its timer fires.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

shell/plugins/services/idle/Service.qml

@@ -267,14 +267,14 @@ Item {
     id: screensaverTimer
     interval: root.screensaverDelaySeconds * 1000
     repeat: false
-    onTriggered: root.launchScreensaver()
+    onTriggered: if (root.screensaverEnabled) root.launchScreensaver()
   }
 
   Timer {
     id: lockTimer
     interval: root.lockDelaySeconds * 1000
     repeat: false
-    onTriggered: if (root.idleEnabled && root.idledThisCycle) root.lockSystem("lock-timeout")
+    onTriggered: if (root.idleEnabled && root.idledThisCycle && root.lockEnabled) root.lockSystem("lock-timeout")
   }
 
   Timer {