feat(examples): update client_app and postly implementation details

- Refactored and updated pages, router, DI modules, and feature implementations in both example projects:
  - client_app: main.dart and my_home_page.dart updated for improved navigation and structure.
  - postly: updated DI wiring, presentation pages, repository implementation, and routing logic.
- Applied small improvements and code consistency changes in the examples.

docs: add new documentation assets and benchmarking script

BREAKING CHANGE:
Examples now reflect the latest changes in the DI framework and are ready for Dart 3.8+ and cherrypick_generator element2 API compatibility.

examples/client_app/lib/my_home_page.dart

@@ -11,12 +11,8 @@ class MyHomePage extends StatelessWidget {
   Widget build(BuildContext context) {
     //_inject(context); // Make sure this function is called in context
     return Scaffold(
-      appBar: AppBar(
-        title: const Text('Example App'),
-      ),
-      body: Center(
-        child: Text(useCase.fetchData()),
-      ),
+      appBar: AppBar(title: const Text('Example App')),
+      body: Center(child: Text(useCase.fetchData())),
     );
   }
 }