feat(core): refonte architecture transverse (cache, network, websocket, DI)

- lib/app : app.dart, router mis à jour (routes nouveaux modules)
- lib/core/cache : cache_service + cached_datasource_decorator
- lib/core/network : api_client, offline_manager, retry_policy
- lib/core/websocket : websocket service (reconnexion exponentielle, heartbeat)
- lib/core/di : injection + register_module
- lib/core/storage : pending_operations_store (offline support)
- lib/core/navigation : main_navigation_layout (onglets par rôle)
- lib/core/config : environment, lcb_ft_constants
- lib/core/utils : error_formatter, validators
- pubspec.yaml/lock : dépendances mises à jour

pubspec.yaml

@@ -83,12 +83,49 @@ dev_dependencies:
   bloc_test: ^9.1.7
   integration_test:
     sdk: flutter
+  flutter_launcher_icons: ^0.13.1
+  flutter_native_splash: ^2.4.1
+
+# ─── Génération des icônes d'application (launcher) ──────────────────────────
+# Source unique : assets/images/unionflow-logo.png
+# Régénérer :  dart run flutter_launcher_icons
+flutter_launcher_icons:
+  android: "ic_launcher"
+  ios: true
+  remove_alpha_ios: true
+  image_path: "assets/images/unionflow-logo.png"
+  background_color_ios: "#FFFFFF"
+  min_sdk_android: 21
+  adaptive_icon_background: "#FFFFFF"
+  adaptive_icon_foreground: "assets/images/unionflow-logo.png"
+  web:
+    generate: false
+  windows:
+    generate: false
+  macos:
+    generate: false
+
+# ─── Génération du splash screen natif (Android + iOS) ───────────────────────
+# Régénérer :  dart run flutter_native_splash:create
+flutter_native_splash:
+  color: "#FFFFFF"
+  color_dark: "#0A0D1A"
+  image: "assets/images/unionflow-logo.png"
+  android_12:
+    image: "assets/images/unionflow-logo.png"
+    color: "#FFFFFF"
+    color_dark: "#0A0D1A"
+  android: true
+  ios: true
+  web: false
+  fullscreen: false
 
 flutter:
   uses-material-design: true
   generate: true
   assets:
     - assets/images/
+    - assets/images/branding/
     - assets/images/payment_methods/wave/
     - assets/images/payment_methods/orange_money/
     - assets/images/payment_methods/free_money/