Update welcome message format in UserController for Kaigen Notifications

- Revised the welcome message sent to users upon Telegram channel configuration to enhance clarity and engagement.
- Included detailed setup information and a friendly greeting to improve user experience.
- Updated notification types to reflect the new features and services provided by the Kaigen notification system.

src/Managing.Api/Controllers/UserController.cs

@@ -112,14 +112,20 @@ public class UserController : BaseController
         {
             try
             {
-                var welcomeMessage = $"🎉 **Trading Bot - Welcome!**\n\n" +
-                                     $"🎯 **Agent:** {user.Name}\n" +
-                                     $"📡 **Channel ID:** {telegramChannel}\n" +
-                                     $"⏰ **Setup Time:** {DateTime.UtcNow:MMM dd, yyyy • HH:mm:ss} UTC\n\n" +
-                                     $"🔔 **Notification Types:**\n" +
-                                     $"• 📈 Position Opens & Closes\n" +
-                                     $"• 🤖 Bot configuration changes\n\n" +
-                                     $"🚀 **Welcome aboard!** Your trading notifications are now live.";
+                var welcomeMessage = $"🎉 **Welcome to Kaigen Notifications!**\n\n" +
+                                     $"Hello {user.AgentName}! 👋\n\n" +
+                                     $"Your Telegram channel has been successfully configured and you're now connected to the Kaigen notification system.\n\n" +
+                                     $"📋 **Your Setup Details:**\n" +
+                                     $"• 🎯 **Agent Name:** {user.AgentName}\n" +
+                                     $"• 📡 **Channel ID:** {telegramChannel}\n" +
+                                     $"• ⏰ **Connected:** {DateTime.UtcNow:MMM dd, yyyy • HH:mm:ss} UTC\n\n" +
+                                     $"🔔 **What You'll Receive:**\n" +
+                                     $"• 📈 Real-time position opens and closes\n" +
+                                     $"• 💰 Trading activity updates\n" +
+                                     $"• 🤖 Strategy and configuration changes\n" +
+                                     $"• ⚠️ Important system alerts\n\n" +
+                                     $"✨ **You're all set!** Start receiving your trading notifications right away. If you have any questions, feel free to reach out.\n\n" +
+                                     $"Happy trading! 🚀";
 
                 await _webhookService.SendMessage(welcomeMessage, telegramChannel);
             }