fix(slideout): yield keyboard focus when modal is open on same screen (#2902)

DankSlideout always held WlrKeyboardFocus.OnDemand regardless of modals,
causing Notepad to steal focus back when Launcher was opened.

ModalManager: clone currentModalsByScreen on mutation so QML bindings
re-evaluate when modals open/close.
DankSlideout: set keyboardFocus to None while a modal is active on the
same screen, letting the modal (launcher) claim focus exclusively.

quickshell/Common/ModalManager.qml

@@ -15,7 +15,11 @@ Singleton {
     function openModal(modal) {
         PopoutManager.screenshotActive = false;
         const screenName = modal.effectiveScreen?.name ?? "unknown";
-        currentModalsByScreen[screenName] = modal;
+        var next = {};
+        for (var k in currentModalsByScreen)
+            next[k] = currentModalsByScreen[k];
+        next[screenName] = modal;
+        currentModalsByScreen = next;
         modalChanged();
         Qt.callLater(() => {
             if (!modal.allowStacking)
@@ -34,7 +38,12 @@ Singleton {
     function closeModal(modal) {
         const screenName = modal.effectiveScreen?.name ?? "unknown";
         if (currentModalsByScreen[screenName] === modal) {
-            delete currentModalsByScreen[screenName];
+            var next = {};
+            for (var k in currentModalsByScreen) {
+                if (k !== screenName)
+                    next[k] = currentModalsByScreen[k];
+            }
+            currentModalsByScreen = next;
             modalChanged();
         }
     }

quickshell/Widgets/DankSlideout.qml

@@ -105,9 +105,11 @@ PanelWindow {
 
     readonly property bool slideoutBlurActive: root.visible && BlurService.enabled && Theme.connectedSurfaceBlurEnabled
 
+    readonly property string _slideoutScreenName: modelData?.name ?? ""
+
     WlrLayershell.layer: (!suppressOverlayLayer && (triggerUsesOverlayLayer || CompositorService.framePeerSurfacesUseOverlayForScreen(modelData))) ? WlrLayershell.Overlay : WlrLayershell.Top
     WlrLayershell.exclusiveZone: 0
-    WlrLayershell.keyboardFocus: isVisible ? WlrKeyboardFocus.OnDemand : WlrKeyboardFocus.None
+    WlrLayershell.keyboardFocus: isVisible && !ModalManager.currentModalsByScreen[_slideoutScreenName] ? WlrKeyboardFocus.OnDemand : WlrKeyboardFocus.None
 
     readonly property real dpr: CompositorService.getScreenScale(root.screen)
     readonly property real alignedWidth: Theme.px(expandable && expandedWidth ? expandedWidthValue : slideoutWidth, dpr)