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>

test/shell.d/idle-test.sh

@@ -33,6 +33,14 @@ assert(
   /if \(root\.lockEnabled\) \{\s*\n\s*if \(root\.lockDelaySeconds === 0\) lockSystem/.test(serviceSource),
   'idle does not lock immediately when lock timeout is disabled'
 )
+assert(
+  /id: screensaverTimer[\s\S]*?onTriggered: if \(root\.screensaverEnabled\) root\.launchScreensaver\(\)/.test(serviceSource),
+  'idle does not launch a pending screensaver once its timeout is set to 0'
+)
+assert(
+  /id: lockTimer[\s\S]*?onTriggered: if \([^)]*root\.lockEnabled\) root\.lockSystem\("lock-timeout"\)/.test(serviceSource),
+  'idle does not fire a pending lock once its timeout is set to 0'
+)
 
 assertDeepEqual(idle.eventParts({ data: 'a,b,c' }, 2), ['a', 'b', 'c'], 'idle parses raw event data')
 assertDeepEqual(