fix(auth): flutter_web_auth_2 + PKCE manuel (retour OIDC fiable via CallbackActivity)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

pubspec.lock

@@ -33,6 +33,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.18.0"
+  crypto:
+    dependency: "direct main"
+    description:
+      name: crypto
+      sha256: c8ea0233063ba03258fbcf2ca4d6dadfefe14f02fab57702265467a19f27fadf
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.0.7"
   cupertino_icons:
     dependency: "direct main"
     description:
@@ -41,6 +49,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.0.8"
+  desktop_webview_window:
+    dependency: transitive
+    description:
+      name: desktop_webview_window
+      sha256: "57cf20d81689d5cbb1adfd0017e96b669398a669d927906073b0e42fc64111c0"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.2.3"
   ffi:
     dependency: transitive
     description:
@@ -62,22 +78,6 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
-  flutter_appauth:
-    dependency: "direct main"
-    description:
-      name: flutter_appauth
-      sha256: "0aa449d8991f70e7847d55b8bff0890fb41dc62c1d8526337e4073e806813bcb"
-      url: "https://pub.dev"
-    source: hosted
-    version: "8.0.3"
-  flutter_appauth_platform_interface:
-    dependency: transitive
-    description:
-      name: flutter_appauth_platform_interface
-      sha256: ccf5e1d8c40dd35b297290b33cc1896648b4b92a2ec3f62a436c62a8eef9a9db
-      url: "https://pub.dev"
-    source: hosted
-    version: "8.0.0"
   flutter_lints:
     dependency: "direct dev"
     description:
@@ -134,6 +134,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "3.1.2"
+  flutter_web_auth_2:
+    dependency: "direct main"
+    description:
+      name: flutter_web_auth_2
+      sha256: "3c14babeaa066c371f3a743f204dd0d348b7d42ffa6fae7a9847a521aff33696"
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.1.0"
+  flutter_web_auth_2_platform_interface:
+    dependency: transitive
+    description:
+      name: flutter_web_auth_2_platform_interface
+      sha256: c63a472c8070998e4e422f6b34a17070e60782ac442107c70000dd1bed645f4d
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.1.0"
   flutter_web_plugins:
     dependency: transitive
     description: flutter
@@ -456,6 +472,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "5.10.1"
+  window_to_front:
+    dependency: transitive
+    description:
+      name: window_to_front
+      sha256: "14fad8984db4415e2eeb30b04bb77140b180e260d6cb66b26de126a8657a9241"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.0.4"
   xdg_directories:
     dependency: transitive
     description: