feat: Implement real-time messaging with socket listeners and enable starting chats from agent details.

lib/features/messaging/data/models/messaging_models.dart

@@ -67,6 +67,18 @@ class OtherParty {
       lastSeenAt: json['lastSeenAt'] as String?,
     );
   }
+
+  OtherParty copyWith({bool? isOnline, String? lastSeenAt}) {
+    return OtherParty(
+      id: id,
+      userId: userId,
+      name: name,
+      avatar: avatar,
+      headline: headline,
+      isOnline: isOnline ?? this.isOnline,
+      lastSeenAt: lastSeenAt ?? this.lastSeenAt,
+    );
+  }
 }
 
 class Conversation {