Introduces repositories, validators, and integration tests for private chats. Refactors group-related models to support invitations and memberships, updates group repository interfaces and implementations, and enhances message service logic to handle private chat creation and retrieval. Also registers new services and validators in DI, and updates related tests.
Introduces comprehensive unit tests for MessageService covering send, edit, and delete message scenarios. Adds and implements IGroupsRepository, IGroupsReader, and IGroupsWriter interfaces with method stubs in GroupRepository. Updates ChatGroup model with Description and ImageId fields, and registers GroupRepository in DI. Fixes parameter order in SendMessage record.