added Type Jam puzzle app for review (#1554)

* added Type Jam puzzle app for review

* pr round 2 prep

* updated ci scripts for varfont_shader_puzzle

* resolved unused and minor variable naming issues

* rotator tiles row and col are final vars now

* removed unused import and print from production

* made constructors const where needed

* pages_flow export refactored to directly come from that file

* removed old api commented out section from FragmentShaded

* updated pubspec yaml to correct project name

* dart min version updated; removed unnecessary commented out dependencies from pubspec.yaml

* updated pubspec.yaml min flutter version to ensure FragmentShader support

* added/edited comments for explanation, esp on var fonts; removed obsolete comments

* trailing newline added to pubspec.yaml eof

experimental/varfont_shader_puzzle/lib/main.dart

@@ -0,0 +1,28 @@
+// Copyright 2023 The Flutter team. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+import 'package:flutter/material.dart';
+import '../page_content/pages_flow.dart';
+
+void main() {
+  runApp(const TypePuzzle());
+}
+
+class TypePuzzle extends StatelessWidget {
+  const TypePuzzle({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      debugShowCheckedModeBanner: false,
+      title: 'Type Jam',
+      theme: ThemeData(
+        primarySwatch: Colors.grey,
+      ),
+      home: const Scaffold(
+        appBar: null,
+        body: PagesFlow(),
+      ),
+    );
+  }
+}