add slide-in applet dock with collapsible cards, edge trigger, and bar module toggle

shell/dock/DockEdgeTrigger.qml

@@ -0,0 +1,32 @@
+import QtQuick
+import Quickshell
+import Quickshell.Wayland
+import "." as D
+
+// Invisible 2px-wide PanelWindow at the right screen edge.
+// When cursor enters, opens the dock in overlay mode.
+PanelWindow {
+    id: root
+
+    required property var screen
+
+    visible: !D.DockState.open
+    color: "transparent"
+
+    WlrLayershell.layer: WlrLayer.Overlay
+    WlrLayershell.exclusiveZone: 0
+    WlrLayershell.namespace: "nova-dock-trigger"
+
+    anchors.top: true
+    anchors.right: true
+    anchors.bottom: true
+
+    implicitWidth: 2
+
+    HoverHandler {
+        onHoveredChanged: {
+            if (hovered && !D.DockState.open)
+                D.DockState.openOverlay();
+        }
+    }
+}