feat: Implement socket-first message sending with REST fallback, enhance chat room re-joining on socket reconnect, and update 'Categories' to 'Specialization' in the hero section.

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

@@ -291,7 +291,20 @@ class MessagingNotifier extends StateNotifier<MessagingState> {
     );
 
     try {
-      final realMessage = await _repository.sendMessage(
+      // Send via socket so the backend broadcasts new_message to the other user.
+      // The REST endpoint does NOT emit socket events, so using REST here
+      // would prevent real-time delivery to the other participant.
+      ChatMessage? realMessage;
+
+      if (_socket.isConnected) {
+        realMessage = await _socket.sendMessage(conversationId, {
+          'content': content,
+          'messageType': 'TEXT',
+        });
+      }
+
+      // Fallback to REST if socket send failed or not connected
+      realMessage ??= await _repository.sendMessage(
         conversationId,
         content: content,
       );
@@ -311,7 +324,7 @@ class MessagingNotifier extends StateNotifier<MessagingState> {
       final updatedConversations = state.conversations.map((c) {
         if (c.id == conversationId) {
           return c.copyWith(
-            lastMessageText: realMessage.content,
+            lastMessageText: realMessage!.content,
             lastMessageAt: realMessage.createdAt,
           );
         }