refactor: Update Twitter OAuth 2.0 PKCE flow for dynamic redirect URI and public client authentication, replace SVG back button with a native icon, and enhance Twitter login error reporting.

lib/features/messaging/presentation/providers/messaging_provider.dart

@@ -75,6 +75,7 @@ class MessagingNotifier extends StateNotifier<MessagingState> {
   MessagingNotifier(this._repository, this._ref)
       : super(const MessagingState()) {
     _initSocketListeners();
+    loadUnreadCount();
   }
 
   String? get _currentUserId => _ref.read(authProvider).user?.id;
@@ -132,9 +133,15 @@ class MessagingNotifier extends StateNotifier<MessagingState> {
         return c;
       }).toList();
 
+      // Recalculate total unread count
+      final totalUnread = updatedConversations.fold<int>(
+        0, (sum, c) => sum + c.unreadCount,
+      );
+
       state = state.copyWith(
         messages: updatedMessages,
         conversations: updatedConversations,
+        unreadCount: totalUnread,
       );
     }));
 
@@ -575,9 +582,13 @@ class MessagingNotifier extends StateNotifier<MessagingState> {
             ..remove(conversationId);
       final updatedConversations =
           state.conversations.where((c) => c.id != conversationId).toList();
+      final totalUnread = updatedConversations.fold<int>(
+        0, (sum, c) => sum + c.unreadCount,
+      );
       state = state.copyWith(
         messages: updatedMessages,
         conversations: updatedConversations,
+        unreadCount: totalUnread,
         clearActiveConversation: true,
       );
     } catch (_) {