Add app source and tests

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

lib/Peach/see/splash/Splash.dart

@@ -0,0 +1,10 @@
+import 'package:flutter/cupertino.dart';
+
+import 'SplashState.dart';
+
+class Splash extends StatefulWidget {
+  const Splash({super.key});
+
+  @override
+  State<Splash> createState() => SplashState();
+}