Implemented per stream subscription recovery with polling fallback

lib/screens/tickets/ticket_detail_screen.dart

@@ -528,29 +528,41 @@ class _TicketDetailScreenState extends ConsumerState<TicketDetailScreen> {
 
     _maybeTypingController(widget.ticketId)?.stopTyping();
 
-    final message = await ref
-        .read(ticketsControllerProvider)
-        .sendTicketMessage(ticketId: widget.ticketId, content: content);
+    // Capture mentions and clear the composer immediately so the UI
+    // remains snappy. Perform the network send and notification creation
+    // in a fire-and-forget background Future.
     final mentionUserIds = _extractMentionedUserIds(
       content,
       profiles,
       currentUserId,
     );
-    if (mentionUserIds.isNotEmpty && currentUserId != null) {
-      await ref
-          .read(notificationsControllerProvider)
-          .createMentionNotifications(
-            userIds: mentionUserIds,
-            actorId: currentUserId,
-            ticketId: widget.ticketId,
-            messageId: message.id,
-          );
-    }
-    ref.invalidate(ticketMessagesProvider(widget.ticketId));
     if (mounted) {
       _messageController.clear();
       _clearMentions();
     }
+
+    Future(() async {
+      try {
+        final message = await ref
+            .read(ticketsControllerProvider)
+            .sendTicketMessage(ticketId: widget.ticketId, content: content);
+
+        if (mentionUserIds.isNotEmpty && currentUserId != null) {
+          try {
+            await ref
+                .read(notificationsControllerProvider)
+                .createMentionNotifications(
+                  userIds: mentionUserIds,
+                  actorId: currentUserId,
+                  ticketId: widget.ticketId,
+                  messageId: message.id,
+                );
+          } catch (_) {}
+        }
+      } catch (e, st) {
+        debugPrint('sendTicketMessage error: $e\n$st');
+      }
+    });
   }
 
   List<String> _extractMentionedUserIds(