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.lock

@@ -17,6 +17,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "8.4.1"
+  ansicolor:
+    dependency: transitive
+    description:
+      name: ansicolor
+      sha256: "50e982d500bc863e1d703448afdbf9e5a72eb48840a4f766fa361ffd6877055f"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.0.3"
   archive:
     dependency: transitive
     description:
@@ -177,6 +185,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.2.0"
+  cli_util:
+    dependency: transitive
+    description:
+      name: cli_util
+      sha256: ff6785f7e9e3c38ac98b2fb035701789de90154024a75b6cb926445e83197d1c
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.4.2"
   clock:
     dependency: transitive
     description:
@@ -249,6 +265,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "3.0.7"
+  csslib:
+    dependency: transitive
+    description:
+      name: csslib
+      sha256: "09bad715f418841f976c77db72d5398dc1253c21fb9c0c7f0b0b985860b2d58e"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.0.2"
   csv:
     dependency: "direct main"
     description:
@@ -451,6 +475,14 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  flutter_launcher_icons:
+    dependency: "direct dev"
+    description:
+      name: flutter_launcher_icons
+      sha256: "526faf84284b86a4cb36d20a5e45147747b7563d921373d4ee0559c54fcdbcea"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.13.1"
   flutter_lints:
     dependency: "direct dev"
     description:
@@ -488,6 +520,14 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  flutter_native_splash:
+    dependency: "direct dev"
+    description:
+      name: flutter_native_splash
+      sha256: "7062602e0dbd29141fb8eb19220b5871ca650be5197ab9c1f193a28b17537bc7"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.4.4"
   flutter_plugin_android_lifecycle:
     dependency: transitive
     description:
@@ -623,6 +663,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.3.2"
+  html:
+    dependency: transitive
+    description:
+      name: html
+      sha256: "6d1264f2dffa1b1101c25a91dff0dc2daee4c18e87cd8538729773c073dbf602"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.15.6"
   http:
     dependency: "direct main"
     description:
@@ -1489,6 +1537,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.4.0"
+  universal_io:
+    dependency: transitive
+    description:
+      name: universal_io
+      sha256: f63cbc48103236abf48e345e07a03ce5757ea86285ed313a6a032596ed9301e2
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.3.1"
   url_launcher:
     dependency: "direct main"
     description: