feat(features): refontes adhesions/admin/auth/backup/contributions/dashboard/epargne/events

- adhesions : bloc complet avec events/states/model, dialogs paiement/rejet
- admin : users bloc, user management list/detail pages
- authentication : bloc + keycloak auth service + webview
- backup : bloc complet, repository, models
- contributions : bloc + widgets + export
- dashboard : widgets connectés (activities, events, notifications, search)
  + charts + monitoring + shortcuts
- epargne : repository, transactions, dialogs
- events : bloc complet, pages (detail, connected, wrapper), models

lib/features/epargne/presentation/widgets/retrait_epargne_dialog.dart

@@ -257,7 +257,7 @@ class _RetraitEpargneDialogState extends State<RetraitEpargneDialog> {
                         )
                       : Icon(
                           _pieceJustificativeId != null ? Icons.check_circle : Icons.attach_file,
-                          color: _pieceJustificativeId != null ? Colors.green : null,
+                          color: _pieceJustificativeId != null ? AppColors.success : null,
                         ),
                   label: Text(
                     _pieceJustificativeId != null
@@ -267,7 +267,7 @@ class _RetraitEpargneDialogState extends State<RetraitEpargneDialog> {
                   style: OutlinedButton.styleFrom(
                     minimumSize: const Size(double.infinity, 48),
                     side: _pieceJustificativeId != null
-                        ? const BorderSide(color: Colors.green)
+                        ? const BorderSide(color: AppColors.success)
                         : null,
                   ),
                 ),
@@ -285,7 +285,7 @@ class _RetraitEpargneDialogState extends State<RetraitEpargneDialog> {
                   child: Text(
                     'Photo ou PDF (max 5 MB)',
                     style: Theme.of(context).textTheme.bodySmall?.copyWith(
-                          color: Colors.grey,
+                          color: AppColors.textTertiary,
                         ),
                   ),
                 ),