feat(bar): add home latency indicator widget

modules/bar/HomeWidget.qml

@@ -0,0 +1,11 @@
+pragma ComponentBehavior: Bound
+
+import qs.ui
+import qs.services
+
+BarButton {
+  hoverHighlight: false
+  pointerCursor: false
+  label: Home.latency >= 0 ? `${Home.latency} ms` : "NA"
+  iconSource: Home.icon
+}