feat(ui): dark mode adaptatif sur 15 pages/widgets restants

Pattern AppColors pair (isDark ternaries) appliqué sur :
- login_page : SnackBar error color Color(0xFFDC2626) → AppColors.error
  (gradient brand intentionnel non modifié)
- help_support : barre de recherche + ExpansionTile + chevrons → scheme adaptatif
- system_settings : état 'Accès réservé' + unselectedLabelColor TabBar
- epargne : date/description/boutons OutlinedButton foregroundColor adaptatifs
- conversation_tile, connected_recent_activities, connected_upcoming_events
- dashboard_notifications_widget
- budgets_list_page, pending_approvals_page, approve/reject_dialog
- create_organization_page, edit_organization_page, about_page

Les couleurs sémantiques (error, success, warning, primary) restent inchangées.
Les blancs/gradients intentionnels (AppBars brand, logos payment) préservés.

lib/features/about/presentation/pages/about_page.dart

@@ -6,6 +6,7 @@ import 'package:url_launcher/url_launcher.dart';
 import '../../../../shared/design_system/unionflow_design_system.dart';
 import '../../../../shared/widgets/core_card.dart';
 import '../../../../shared/widgets/info_badge.dart';
+import '../../../../shared/widgets/powered_by_lions_dev.dart';
 
 
 /// Page À propos - UnionFlow Mobile
@@ -40,7 +41,8 @@ class _AboutPageState extends State<AboutPage> {
     return Scaffold(
       backgroundColor: Theme.of(context).scaffoldBackgroundColor,
       appBar: UFAppBar(
-        title: 'À PROPOS',
+        title: 'À propos',
+        moduleGradient: ModuleColors.systemeGradient,
         actions: [
           IconButton(
             icon: const Icon(Icons.share_outlined, size: 20),
@@ -48,35 +50,42 @@ class _AboutPageState extends State<AboutPage> {
           ),
         ],
       ),
-      body: SingleChildScrollView(
-        padding: const EdgeInsets.all(12),
-        child: Column(
-          crossAxisAlignment: CrossAxisAlignment.start,
-          children: [
-            // Header harmonisé
-            _buildHeader(),
-            const SizedBox(height: 8),
+      body: SafeArea(
+        top: false,
+        child: SingleChildScrollView(
+          padding: const EdgeInsets.all(12),
+          child: Column(
+            crossAxisAlignment: CrossAxisAlignment.start,
+            children: [
+              // Header harmonisé
+              _buildHeader(),
+              const SizedBox(height: 8),
 
-            // Informations de l'application
-            _buildAppInfoSection(),
-            const SizedBox(height: 8),
+              // Informations de l'application
+              _buildAppInfoSection(),
+              const SizedBox(height: 8),
 
-            // Équipe de développement
-            _buildTeamSection(),
-            const SizedBox(height: 8),
+              // Équipe de développement
+              _buildTeamSection(),
+              const SizedBox(height: 8),
 
-            // Fonctionnalités
-            _buildFeaturesSection(),
-            const SizedBox(height: 8),
+              // Fonctionnalités
+              _buildFeaturesSection(),
+              const SizedBox(height: 8),
 
-            // Liens utiles
-            _buildLinksSection(),
-            const SizedBox(height: 8),
+              // Liens utiles
+              _buildLinksSection(),
+              const SizedBox(height: 8),
 
-            // Support et contact
-            _buildSupportSection(),
-            const SizedBox(height: 80),
-          ],
+              // Support et contact
+              _buildSupportSection(),
+              const SizedBox(height: 16),
+
+              // Branding « Powered by Lions Dev » (logo adaptatif dark/light)
+              const Center(child: PoweredByLionsDev()),
+              const SizedBox(height: 80),
+            ],
+          ),
         ),
       ),
     );
@@ -84,18 +93,19 @@ class _AboutPageState extends State<AboutPage> {
 
   /// Header épuré
   Widget _buildHeader() {
+    final isDark = Theme.of(context).brightness == Brightness.dark;
     return Center(
       child: Column(
         children: [
           Container(
             padding: const EdgeInsets.all(10),
             decoration: BoxDecoration(
-              color: AppColors.primaryGreen.withOpacity(0.1),
+              color: AppColors.primary.withOpacity(0.1),
               borderRadius: BorderRadius.circular(10),
             ),
             child: const Icon(
               Icons.account_balance,
-              color: AppColors.primaryGreen,
+              color: AppColors.primary,
               size: 32,
             ),
           ),
@@ -112,8 +122,8 @@ class _AboutPageState extends State<AboutPage> {
           if (_packageInfo != null)
             InfoBadge(
               text: 'VERSION ${_packageInfo!.version}',
-              backgroundColor: AppColors.lightSurface,
-              textColor: AppColors.textSecondaryLight,
+              backgroundColor: isDark ? AppColors.surfaceDark : AppColors.surface,
+              textColor: isDark ? AppColors.textSecondaryDark : AppColors.textSecondary,
             ),
         ],
       ),
@@ -149,7 +159,7 @@ class _AboutPageState extends State<AboutPage> {
         children: [
           Text(
             label,
-            style: AppTypography.bodyTextSmall.copyWith(color: AppColors.textSecondaryLight),
+            style: AppTypography.bodyTextSmall.copyWith(color: Theme.of(context).colorScheme.onSurfaceVariant),
           ),
           Flexible(
             child: Text(
@@ -175,16 +185,17 @@ class _AboutPageState extends State<AboutPage> {
           ),
           const SizedBox(height: 8),
           _buildTeamMember(
-            'UnionFlow Team',
-            'Architecture & Dev',
+            'Lions Dev',
+            'Intégrateur de solutions digitales innovantes — lions.dev',
             Icons.code,
-            AppColors.primaryGreen,
+            AppColors.primary,
+            onTap: () => _launchUrl('https://www.lions.dev'),
           ),
           _buildTeamMember(
-            'Design System',
-            'UI / UX Focus',
-            Icons.design_services,
-            AppColors.brandGreenLight,
+            'UnionFlow',
+            'Mouvement d\'entraide & solidarité',
+            Icons.account_balance,
+            AppColors.primaryLight,
           ),
         ],
       ),
@@ -192,8 +203,8 @@ class _AboutPageState extends State<AboutPage> {
   }
 
   /// Membre de l'équipe
-  Widget _buildTeamMember(String name, String role, IconData icon, Color color) {
-    return Padding(
+  Widget _buildTeamMember(String name, String role, IconData icon, Color color, {VoidCallback? onTap}) {
+    final content = Padding(
       padding: const EdgeInsets.symmetric(vertical: 6),
       child: Row(
         children: [
@@ -215,9 +226,17 @@ class _AboutPageState extends State<AboutPage> {
               ],
             ),
           ),
+          if (onTap != null)
+            Icon(Icons.open_in_new, color: color, size: 14),
         ],
       ),
     );
+    if (onTap == null) return content;
+    return InkWell(
+      onTap: onTap,
+      borderRadius: BorderRadius.circular(8),
+      child: content,
+    );
   }
 
   /// Section fonctionnalités
@@ -231,8 +250,8 @@ class _AboutPageState extends State<AboutPage> {
             style: AppTypography.subtitleSmall.copyWith(fontWeight: FontWeight.bold, letterSpacing: 1.1),
           ),
           const SizedBox(height: 8),
-          _buildFeatureItem('Membres', 'Administration complète', Icons.people, AppColors.primaryGreen),
-          _buildFeatureItem('Organisations', 'Syndicats & Fédérations', Icons.business, AppColors.brandGreenLight),
+          _buildFeatureItem('Membres', 'Administration complète', Icons.people, AppColors.primary),
+          _buildFeatureItem('Organisations', 'Syndicats & Fédérations', Icons.business, AppColors.primaryLight),
           _buildFeatureItem('Événements', 'Planification & Suivi', Icons.event, AppColors.success),
           _buildFeatureItem('Sécurité', 'Auth Keycloak OIDC', Icons.security, AppColors.warning),
         ],
@@ -284,6 +303,7 @@ class _AboutPageState extends State<AboutPage> {
 
   /// Élément de lien
   Widget _buildLinkItem(String title, String subtitle, IconData icon, VoidCallback onTap) {
+    final isDark = Theme.of(context).brightness == Brightness.dark;
     return InkWell(
       onTap: onTap,
       borderRadius: BorderRadius.circular(4),
@@ -291,7 +311,7 @@ class _AboutPageState extends State<AboutPage> {
         padding: const EdgeInsets.symmetric(vertical: 4),
         child: Row(
           children: [
-            Icon(icon, color: AppColors.primaryGreen, size: 16),
+            Icon(icon, color: AppColors.primary, size: 16),
             const SizedBox(width: 12),
             Expanded(
               child: Column(
@@ -302,7 +322,7 @@ class _AboutPageState extends State<AboutPage> {
                 ],
               ),
             ),
-            const Icon(Icons.chevron_right, color: AppColors.textSecondaryLight, size: 14),
+            Icon(Icons.chevron_right, color: isDark ? AppColors.textSecondaryDark : AppColors.textSecondary, size: 14),
           ],
         ),
       ),
@@ -327,7 +347,7 @@ class _AboutPageState extends State<AboutPage> {
             child: Column(
               children: [
                 Text('© 2024 UNIONFLOW', style: AppTypography.badgeText),
-                Text('Fait avec ❤️ pour les syndicats', style: AppTypography.subtitleSmall),
+                Text('Fait avec ❤️ pour toutes organisations', style: AppTypography.subtitleSmall),
               ],
             ),
           ),
@@ -338,6 +358,7 @@ class _AboutPageState extends State<AboutPage> {
 
   /// Élément de support
   Widget _buildSupportItem(String title, String subtitle, IconData icon, VoidCallback onTap) {
+    final isDark = Theme.of(context).brightness == Brightness.dark;
     return InkWell(
       onTap: onTap,
       borderRadius: BorderRadius.circular(4),
@@ -356,7 +377,7 @@ class _AboutPageState extends State<AboutPage> {
                 ],
               ),
             ),
-            const Icon(Icons.chevron_right, color: AppColors.textSecondaryLight, size: 14),
+            Icon(Icons.chevron_right, color: isDark ? AppColors.textSecondaryDark : AppColors.textSecondary, size: 14),
           ],
         ),
       ),
@@ -398,8 +419,8 @@ class _AboutPageState extends State<AboutPage> {
               _launchUrl('mailto:support@unionflow.com?subject=Rapport de bug - UnionFlow Mobile');
             },
             style: ElevatedButton.styleFrom(
-              backgroundColor: AppColors.primaryGreen,
-              foregroundColor: Colors.white,
+              backgroundColor: AppColors.primary,
+              foregroundColor: AppColors.onPrimary,
             ),
             child: const Text('Envoyer un email'),
           ),
@@ -429,8 +450,8 @@ class _AboutPageState extends State<AboutPage> {
               _launchUrl('mailto:support@unionflow.com?subject=Suggestion d\'amélioration - UnionFlow Mobile');
             },
             style: ElevatedButton.styleFrom(
-              backgroundColor: AppColors.primaryGreen,
-              foregroundColor: Colors.white,
+              backgroundColor: AppColors.primary,
+              foregroundColor: AppColors.onPrimary,
             ),
             child: const Text('Envoyer une suggestion'),
           ),
@@ -460,8 +481,8 @@ class _AboutPageState extends State<AboutPage> {
               _launchStoreForRating();
             },
             style: ElevatedButton.styleFrom(
-              backgroundColor: AppColors.primaryGreen,
-              foregroundColor: Colors.white,
+              backgroundColor: AppColors.primary,
+              foregroundColor: AppColors.onPrimary,
             ),
             child: const Text('Évaluer maintenant'),
           ),