refactor(compositor): reduce unnecessary UI updates

- Defer updates when window state hasn't actually changed
- Cache frame-blocked state per screen instead of recalculating constantly
- keep popouts cache so reopening them is instant & clean up otherwise

quickshell/Widgets/DankPopoutStandalone.qml

@@ -57,6 +57,7 @@ Item {
     property bool contentHandlesKeys: false
     property bool fullHeightSurface: false
     property bool _primeContent: false
+    property bool _contentWarm: false
     property bool _resizeActive: false
     property real _surfaceMarginLeft: 0
     property real _surfaceMarginTop: 0
@@ -305,6 +306,7 @@ Item {
         isClosing = false;
         animationsEnabled = false;
         _primeContent = true;
+        _contentWarm = true;
 
         _frozenMaskX = maskX;
         _frozenMaskY = maskY;
@@ -891,7 +893,8 @@ Item {
                         Loader {
                             id: contentLoader
                             anchors.fill: parent
-                            active: root._primeContent || shouldBeVisible || contentWindow.visible
+                            // _contentWarm keeps the tree loaded across close for fast re-open; reclaimed by PopoutService on lock/idle.
+                            active: root._primeContent || shouldBeVisible || contentWindow.visible || root._contentWarm
                             asynchronous: false
                         }
                     }