refactor(fullscreen): Refine fullscreen layering and frame overlay behavior

- Replaced fullscreen hide/reveal toggles with Show Over Fullscreen layer toggles
- Added Launcher opt to Show Over Fullscreen setting
- Kept fullscreen stacking compositor-owned via top/overlay layer choices
- Fixed Hyrland Special Workspaces
- Updated DMS Advanced Configuration docs

quickshell/Widgets/DankSlideout.qml

@@ -15,6 +15,7 @@ PanelWindow {
     property bool isVisible: false
     property var targetScreen: null
     property var modelData: null
+    property bool triggerUsesOverlayLayer: false
     property real slideoutWidth: 480
     property bool expandable: false
     property bool expandedWidth: false
@@ -61,7 +62,7 @@ PanelWindow {
 
     readonly property bool slideoutBlurActive: root.visible && BlurService.enabled && Theme.connectedSurfaceBlurEnabled
 
-    WlrLayershell.layer: WlrLayershell.Top
+    WlrLayershell.layer: (triggerUsesOverlayLayer || CompositorService.framePeerSurfacesUseOverlayForScreen(modelData)) ? WlrLayershell.Overlay : WlrLayershell.Top
     WlrLayershell.exclusiveZone: 0
     WlrLayershell.keyboardFocus: isVisible ? WlrKeyboardFocus.OnDemand : WlrKeyboardFocus.None