Migrate veggieseasons to go_router (#1544)

* add go_router

* wip migration to go_router

* small fixes

* home screen cleanup

* remove unused

* small fixes

* details should be fullscreen dialog

* remove comment

* fix navigation outside the shell by using the correct navigation keys

* add restoration id to all pages

* test passing, but parts are commented out, wip

* uncommented more test code

* Add TODOs

* fix lint issues

* fix tests

* use FadeTransitionPage

* remove unnecessary builders

* FadeTransitionPage same as CustomTransitionPage

* add comments regarding relative routes

* add missing pageKey

* add missing const

---------

Co-authored-by: Brett Morgan <brettmorgan@google.com>

veggieseasons/lib/widgets/veggie_headline.dart

@@ -3,8 +3,8 @@
 // found in the LICENSE file.
 
 import 'package:flutter/cupertino.dart';
+import 'package:go_router/go_router.dart';
 import 'package:veggieseasons/data/veggie.dart';
-import 'package:veggieseasons/screens/details.dart';
 import 'package:veggieseasons/styles.dart';
 
 class ZoomClipAssetImage extends StatelessWidget {
@@ -72,7 +72,13 @@ class VeggieHeadline extends StatelessWidget {
     final themeData = CupertinoTheme.of(context);
 
     return GestureDetector(
-      onTap: () => DetailsScreen.show(Navigator.of(context), veggie.id),
+      onTap: () {
+        // GoRouter does not support relative routes,
+        // so navigate to the absolute route, which can be either
+        // `/favorites/details/${veggie.id}` or `/search/details/${veggie.id}`
+        // see https://github.com/flutter/flutter/issues/108177
+        context.go('${GoRouter.of(context).location}/details/${veggie.id}');
+      },
       child: Row(
         crossAxisAlignment: CrossAxisAlignment.start,
         children: [