fix(updater): restore Qt release checks and signed installation

cx

crates/qbz-qt/qml/shell/HeaderBar.qml

@@ -1497,6 +1497,14 @@ Rectangle {
                     root.reportIssueRequested()
                 }
             }
+            AppMenuItem {
+                name: "refresh-cw"
+                label: QbzSession.tr("Check for updates now", QbzSession.trRev)
+                onClicked: {
+                    appMenu.close()
+                    QbzAbout.updatesCheck()
+                }
+            }
             AppMenuItem {
                 name: "wand-sparkles"
                 label: QbzSession.tr("What's New", QbzSession.trRev)