Refactor routing methods to Navi helper class

flutter/lib/utils/navi.dart

@@ -1 +1,11 @@
-class Navi {}
+import 'package:flutter/material.dart';
+
+class Navi {
+  static void push<T extends Widget>(BuildContext context, T Function() builder) {
+    Navigator.push(context, MaterialPageRoute<T>(builder: (context) => builder()));
+  }
+
+  static void popToRoot(BuildContext context) {
+    Navigator.popUntil(context, (route) => route.isFirst);
+  }
+}