Update README with project structure and Clean Architecture overview

finlog_app/app/README.md

@@ -1,16 +1,46 @@
-# app
+# Project Structure
 
-A new Flutter project.
+The project follows a **Clean Architecture inspired** structure with clear separation into **app**, **core**, and *
+*features**.
 
-## Getting Started
+```text
+lib/
+  app/                       → app-wide modules (theme, router, DI, env)
+    router.dart              → global routing (go_router)
+    theme.dart               → app theme and styling
+    di.dart                  → dependency injection (providers, locator)
 
-This project is a starting point for a Flutter application.
+  core/                      → shared, generic & stable components
+    network/                 → Dio client, interceptors
+    storage/                 → secure/local storage abstractions
+    error/                   → Failure, AppException, guards
+    utils/                   → formatters, validators, helpers
+    result.dart              → Either/Result type
 
-A few resources to get you started if this is your first Flutter project:
+  features/
+    inventory/
+      data/
+        models/              → DTOs (Json)
+        sources/             → remote/local data sources
+        repositories/        → implementations (InventoryRepositoryImpl)
+      domain/
+        entities/            → pure Dart objects (business entities)
+        repositories/        → abstract definitions (InventoryRepository)
+        usecases/            → business logic (AddItem, ScanBarcode, …)
+      presentation/
+        pages/
+          inventory_page.dart
+          add_item_page.dart
+        controllers/         → state management (Riverpod/BLoC) & presenters
+        widgets/             → feature-specific UI components
+      inventory_routes.dart  → go_router routes for this feature
 
-- [Lab: Write your first Flutter app](https://docs.flutter.dev/get-started/codelab)
-- [Cookbook: Useful Flutter samples](https://docs.flutter.dev/cookbook)
+    budget/                  → same structure as inventory
+    expenses/                → same structure as inventory
+    auth/                    → same structure as inventory
 
-For help getting started with Flutter development, view the
-[online documentation](https://docs.flutter.dev/), which offers tutorials,
-samples, guidance on mobile development, and a full API reference.
+  main.dart                  → application entry point
+```
+# Layered Flow
+
+Data Source → Repository Impl → Repository Abstraction → UseCase → Controller → UI (Pages/Widgets)