fix(osd): ensure OSD appears on all monitors after resume (#2453)

Some monitors, especially cheaper models, are slow to power on after sleep and may not be present in Quickshell.screens
when onScreensChanged is triggered. This change adds a 3-second delay before updating currentOSDsByScreen to ensure all
screens are detected, mitigating the issue of OSDs not appearing on certain monitors after resume.

Co-authored-by: Klesh Wong <kleshwong@gmail.com>

quickshell/Common/OSDManager.qml

@@ -9,9 +9,11 @@ Singleton {
 
     property var currentOSDsByScreen: ({})
 
-    Connections {
-        target: Quickshell
-        function onScreensChanged() {
+    Timer {
+        id: screensChangedDelayTimer
+        interval: 3000 // 3 seconds
+        repeat: false
+        onTriggered: {
             const activeNames = {};
             for (let i = 0; i < Quickshell.screens.length; i++)
                 activeNames[Quickshell.screens[i].name] = true;
@@ -22,6 +24,12 @@ Singleton {
             }
         }
     }
+    Connections {
+        target: Quickshell
+        function onScreensChanged() {
+            screensChangedDelayTimer.restart();
+        }
+    }
 
     function showOSD(osd) {
         if (!osd || !osd.screen)