Chat represents a chat entity with its details.

ChatParticipant represents a participant in a chat.

Message represents a chat message.

User represents a user in the system.

UserResponse is the format used for sending user data in API responses.

UserSettings represents the settings of a user, including their preferences for theme and message color.

UserToken represents an authentication token for a user.

UserUpdate represents the fields that can be updated in a user's profile.