feat: add read receipt handling based on user preferences

- Integrated `UsersService` into `MessagesService` for retrieving user preferences.
- Updated `markAsRead` functionality to respect `showReadReceipts` preference.
- Enhanced real-time read receipt notifications via `EventsGateway`.
- Added `markAsRead` method to the frontend message service.

backend/src/messages/messages.service.spec.ts

@@ -1,6 +1,7 @@
 import { ForbiddenException } from "@nestjs/common";
 import { Test, TestingModule } from "@nestjs/testing";
 import { EventsGateway } from "../realtime/events.gateway";
+import { UsersService } from "../users/users.service";
 import { MessagesService } from "./messages.service";
 import { MessagesRepository } from "./repositories/messages.repository";
 
@@ -16,6 +17,7 @@ describe("MessagesService", () => {
 		createMessage: jest.fn(),
 		findAllConversations: jest.fn(),
 		isParticipant: jest.fn(),
+		getParticipants: jest.fn(),
 		findMessagesByConversationId: jest.fn(),
 		markAsRead: jest.fn(),
 		countUnreadMessages: jest.fn(),
@@ -25,12 +27,17 @@ describe("MessagesService", () => {
 		sendToUser: jest.fn(),
 	};
 
+	const mockUsersService = {
+		findOne: jest.fn(),
+	};
+
 	beforeEach(async () => {
 		const module: TestingModule = await Test.createTestingModule({
 			providers: [
 				MessagesService,
 				{ provide: MessagesRepository, useValue: mockMessagesRepository },
 				{ provide: EventsGateway, useValue: mockEventsGateway },
+				{ provide: UsersService, useValue: mockUsersService },
 			],
 		}).compile();