fix(slint): track drag no longer stays glued after release

The drag-end relied on the row TouchArea's pointer-up, which only arrives
if the row still holds the grab. Inside a ListView (or a Flickable that
stays interactive) the scroll gesture can steal the grab mid-drag, so the
up never reached the row and the ghost stayed glued to the cursor. Add a
`changed pressed` safety net that ends the drag on any release or grab
cancel (both paths guard on ta.dragging, so end() runs once). Also give
LabelPageView's Flickable the interactive: !DragState.active flag the
other track views already have.

cc

crates/qbz-slint/ui/label/LabelPageView.slint

@@ -12,7 +12,7 @@
 import { Theme } from "../foundation/semantic-colors.slint";
 import { Typography } from "../foundation/typography.slint";
 import { Radius } from "../foundation/radius.slint";
-import { LabelState, LabelActions, TrackItem } from "../state.slint";
+import { LabelState, LabelActions, TrackItem, DragState } from "../state.slint";
 import { QbzIcon } from "../primitives/QbzIcon.slint";
 import { TrackRow } from "../primitives/TrackRow.slint";
 import { CircleAction } from "../primitives/CircleAction.slint";
@@ -47,6 +47,9 @@ export component LabelPageView inherits Rectangle {
     background: Theme.surface-main;
 
     page-flickable := Flickable {
+        // Don't scroll while a track is being dragged out (keeps the row's
+        // pointer grab so the drag-end fires) — matches the other track views.
+        interactive: !DragState.active;
         viewport-width: self.width;
         viewport-height: page.preferred-height;
 

crates/qbz-slint/ui/primitives/TrackRow.slint

@@ -105,6 +105,19 @@ export component TrackRow inherits Rectangle {
                 ta.dragging = false;
             }
         }
+        // Safety net: the `up` above only arrives if this TouchArea still holds
+        // the pointer grab. Inside a ListView (or a Flickable that didn't drop
+        // out of `interactive`), the scroll gesture can steal the grab mid-drag,
+        // so the `up` never reaches us and the ghost stays glued to the cursor.
+        // `pressed` flips to false on BOTH a normal release and a grab cancel,
+        // so ending the drag here guarantees it always clears. Both paths guard
+        // on `ta.dragging`, so whichever fires first wins and end() runs once.
+        changed pressed => {
+            if (!self.pressed && ta.dragging) {
+                DragActions.end();
+                ta.dragging = false;
+            }
+        }
         moved => {
             if (ta.pressed && root.draggable) {
                 if (!ta.dragging