feat: add ComingSoonScreen, integrate it into routing, and update chat avatar and home menu navigation

lib/features/messaging/presentation/screens/chat_screen.dart

@@ -1397,8 +1397,12 @@ class _ChatScreenState extends ConsumerState<ChatScreen>
           ),
         ),
         const SizedBox(width: 10),
-        // Avatar
-        _buildMessageAvatar(null, senderName, 45),
+        // Avatar — use current user's avatar for sent messages
+        _buildMessageAvatar(
+          ref.read(authProvider).user?.avatar,
+          senderName,
+          45,
+        ),
       ],
     );
   }