feat: 构建flutter 基座

test/widget_test.dart

@@ -0,0 +1,9 @@
+import 'package:flutter/widgets.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:im_webview_app/main.dart';
+
+void main() {
+  test('creates the WebView shell app widget', () {
+    expect(const ImWebViewApp(), isA<Widget>());
+  });
+}