fix: improve chat message deduplication, add conversation refresh logic, and update UI components for consistency

lib/features/support_chat/presentation/providers/support_chat_provider.dart

@@ -77,6 +77,9 @@ class SupportChatNotifier extends StateNotifier<SupportChatState> {
     }
   }
 
+  // Track message IDs we've sent via REST to avoid socket echo duplicates
+  final Set<String> _sentMessageIds = {};
+
   Future<void> sendMessage(String content) async {
     final chat = state.chat;
     if (chat == null || content.trim().isEmpty) return;
@@ -85,6 +88,7 @@ class SupportChatNotifier extends StateNotifier<SupportChatState> {
     state = state.copyWith(isSending: true);
     try {
       final message = await _repo.sendMessage(chat.id, content.trim());
+      _sentMessageIds.add(message.id);
       // Dedup — socket broadcast may have already added this message
       if (!state.messages.any((m) => m.id == message.id)) {
         state = state.copyWith(
@@ -121,7 +125,9 @@ class SupportChatNotifier extends StateNotifier<SupportChatState> {
 
   void addIncomingMessage(SupportMessage message) {
     if (state.chat == null || message.chatId != state.chat!.id) return;
+    // Skip if already in list OR if we sent this via REST (socket echo)
     if (state.messages.any((m) => m.id == message.id)) return;
+    if (_sentMessageIds.contains(message.id)) return;
 
     state = state.copyWith(messages: [...state.messages, message]);
     _repo.markAsRead(state.chat!.id);