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/Modules/Plugins/BasePill.qml

@@ -1,4 +1,5 @@
 import QtQuick
+import Quickshell
 import qs.Common
 import qs.Services
 import qs.Widgets
@@ -38,6 +39,18 @@ Item {
     readonly property real rightMargin: !isVerticalOrientation ? (isRightBarEdge && isLast ? barEdgeExtension : (isLast ? gapExtension : gapExtension / 2)) : 0
     readonly property real topMargin: isVerticalOrientation ? (isTopBarEdge && isFirst ? barEdgeExtension : (isFirst ? gapExtension : gapExtension / 2)) : 0
     readonly property real bottomMargin: isVerticalOrientation ? (isBottomBarEdge && isLast ? barEdgeExtension : (isLast ? gapExtension : gapExtension / 2)) : 0
+    readonly property bool barUsesOverlayLayer: {
+        switch (Quickshell.env("DMS_DANKBAR_LAYER")) {
+        case "overlay":
+            return true;
+        case "bottom":
+        case "background":
+        case "top":
+            return false;
+        default:
+            return (barConfig?.showOverFullscreen ?? false) || CompositorService.framePeerSurfacesUseOverlayForScreen(parentScreen);
+        }
+    }
 
     signal clicked
     signal rightClicked(real rootX, real rootY)