Use Tab to switch bar panels

shell/plugins/panels/tailscale/Panel.qml

@@ -296,6 +296,7 @@ Panel {
       }
       onActivateRequested: if (root.cursorActive) root.activateCursor()
       onCloseRequested: root.close()
+      onTabRequested: function(direction) { root.switchPanel(direction) }
       onTextKey: function(t) {
         if (t === "t" || t === "T") tailscale.toggleTailscale()
         else if (t === "c" || t === "C") tailscale.copyPeerIp(root.selectedPeer())