qml: restore Send/ScanDialog for desktop/dev, keeping qr scan Activity for android only.

Also use stable R package, regardless of APP_PACKAGE_DOMAIN used in build.

electrum/gui/qml/components/main.qml

@@ -377,13 +377,19 @@ ApplicationWindow
         }
     }
 
-    property alias scanDialog: _scanDialog
+    property Component scanDialog  // set in Component.onCompleted
     Component {
         id: _scanDialog
         QRScanner {
             //onClosed: destroy()
         }
     }
+    Component {
+        id: _qtScanDialog
+        ScanDialog {
+            onClosed: destroy()
+        }
+    }
 
     property alias channelOpenProgressDialog: _channelOpenProgressDialog
     ChannelOpenProgressDialog {
@@ -434,6 +440,12 @@ ApplicationWindow
     Component.onCompleted: {
         coverTimer.start()
 
+        if (AppController.isAndroid()) {
+            app.scanDialog = _scanDialog
+        } else {
+            app.scanDialog = _qtScanDialog
+        }
+
         if (!Config.autoConnectDefined) {
             var dialog = serverConnectWizard.createObject(app)
             // without completed serverConnectWizard we can't start