test: add unit tests for messaging, comments, events, and user services

- Added comprehensive unit tests for `MessagesService`, `CommentsService`, `EventsGateway`, and enhancements in `UsersService`.
- Ensured proper mocking and test coverage for newly introduced dependencies like `EventsGateway` and `RBACService`.

backend/src/users/users.service.spec.ts

@@ -108,6 +108,7 @@ describe("UsersService", () => {
 	describe("findOne", () => {
 		it("should find a user", async () => {
 			mockUsersRepository.findOne.mockResolvedValue({ uuid: "uuid1" });
+			mockRbacService.getUserRoles.mockResolvedValue([]);
 			const result = await service.findOne("uuid1");
 			expect(result.uuid).toBe("uuid1");
 		});
@@ -139,6 +140,7 @@ describe("UsersService", () => {
 	describe("findByEmailHash", () => {
 		it("should call repository.findByEmailHash", async () => {
 			mockUsersRepository.findByEmailHash.mockResolvedValue({ uuid: "u1" });
+			mockRbacService.getUserRoles.mockResolvedValue([]);
 			const result = await service.findByEmailHash("hash");
 			expect(result.uuid).toBe("u1");
 			expect(mockUsersRepository.findByEmailHash).toHaveBeenCalledWith("hash");