Stop the bar sticking in move mode after a press-and-hold on a widget (#6943)

Bar widgets propagate their composed press-and-hold down to the center gesture
area without handing over the grab, so the gesture area started a bar move and
then received neither a release nor a cancel to end it. The move ghost stayed on
screen for the rest of the session. Ignore the gesture unless we hold the press.

Closes #6881

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

shell/plugins/bar/Bar.qml

@@ -1417,6 +1417,9 @@ Item {
     }
 
     onPressAndHold: function(mouse) {
+      // A widget above us propagates its composed press-and-hold down here without
+      // ever handing over the grab, so we'd get no release or cancel to end the move.
+      if (!gestureArea.pressed) return
       startDrag(mouse.x, mouse.y)
     }
 

test/shell.d/bar-test.sh

@@ -14,6 +14,17 @@ if rg -q 'barMoveSettling|barMoveSettleTimer' "$ROOT/shell/plugins/bar/Bar.qml";
 fi
 pass "bar move outline has no post-release settling state"
 
+# A widget above the gesture area propagates its composed press-and-hold down
+# without handing over the grab, so the resulting move gets neither a release
+# nor a cancel and the ghost stays up for the session. Only the grabbing area
+# reports pressed, which is what separates the two, so the guard has to stay
+# ahead of the drag.
+if ! perl -0ne 'exit(/onPressAndHold:\s*function[^{]*\{[^}]*?\bpressed\b[^}]*?\bstartDrag\b/s ? 0 : 1)' \
+  "$ROOT/shell/plugins/bar/Bar.qml"; then
+  fail "bar move ignores a press-and-hold the gesture area does not hold the press for"
+fi
+pass "bar move ignores a press-and-hold propagated from a widget above"
+
 run_node_test <<'JS'
 const fs = require('fs')
 const bar = requireFromRoot('shell/plugins/bar/BarModel.js')