feat(bar): popouts drop down from the top bar — Phase B

The bar hover fly-outs (wifi/audio/bluetooth/tray/active-window) slid out
sideways from the old left edge; now they drop DOWN from the top bar:

- ClipWrapper.qml: the collapsing/slide axis is now height (was width); the
  popout is positioned along the bar by x (from the hovered widget's x-centre,
  via currentCenter) and docks at the top edge; the dock<->detach animation
  guard moves to the x (along-bar) axis. The content slides in via a negative
  top margin instead of left margin.
- Wrapper.qml: mirror the size-transition animation guards (height is now the
  always-animated extent axis, width the gated along-bar axis).

Verified live in the dev VM: all popouts open downward under their widget.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

modules/bar/popouts/ClipWrapper.qml

@@ -12,21 +12,24 @@ Item {
     required property real borderThickness
 
     readonly property alias content: content
-    property real offsetScale: x > 0 || content.hasCurrent ? 0 : 1
+    property real offsetScale: y > 0 || content.hasCurrent ? 0 : 1
 
     visible: width > 0 && height > 0
     clip: true
 
-    implicitWidth: content.implicitWidth * (1 - offsetScale)
-    implicitHeight: content.implicitHeight
+    // NoSignal top bar: popouts drop DOWN from the bar. The collapsing axis is
+    // now height (was width for the vertical left bar); position along the bar
+    // is x (from the hovered widget's x-centre), the docked edge is the top.
+    implicitWidth: content.implicitWidth
+    implicitHeight: content.implicitHeight * (1 - offsetScale)
 
-    x: content.isDetached ? (parent.width - content.nonAnimWidth) / 2 : 0
-    y: {
+    y: content.isDetached ? (parent.height - content.nonAnimHeight) / 2 : 0
+    x: {
         if (content.isDetached)
-            return (parent.height - content.nonAnimHeight) / 2;
+            return (parent.width - content.nonAnimWidth) / 2;
 
-        const off = content.currentCenter - borderThickness - content.nonAnimHeight / 2;
-        const diff = parent.height - Math.floor(off + content.nonAnimHeight);
+        const off = content.currentCenter - borderThickness - content.nonAnimWidth / 2;
+        const diff = parent.width - Math.floor(off + content.nonAnimWidth);
         if (diff < 0)
             return off + diff;
         return Math.max(off, 0);
@@ -36,14 +39,14 @@ Item {
         Anim {}
     }
 
-    Behavior on x {
+    Behavior on y {
         Anim {
             duration: content.animLength
             easing: content.animCurve
         }
     }
 
-    Behavior on y {
+    Behavior on x {
         enabled: root.offsetScale < 1
 
         Anim {
@@ -58,8 +61,8 @@ Item {
         screen: root.screen
         offsetScale: root.offsetScale
 
-        anchors.verticalCenter: parent.verticalCenter
-        anchors.left: parent.left
-        anchors.leftMargin: (-implicitWidth - 5) * root.offsetScale
+        anchors.horizontalCenter: parent.horizontalCenter
+        anchors.top: parent.top
+        anchors.topMargin: (-implicitHeight - 5) * root.offsetScale
     }
 }

modules/bar/popouts/Wrapper.qml

@@ -149,14 +149,14 @@ Item {
         }
     }
 
-    Behavior on implicitWidth {
+    Behavior on implicitHeight {
         Anim {
             duration: root.animLength
             easing: root.animCurve
         }
     }
 
-    Behavior on implicitHeight {
+    Behavior on implicitWidth {
         enabled: root.offsetScale < 1
 
         Anim {