Refactor code structure for improved readability and maintainability

backend/dist/auth/auth.service.d.ts

@@ -0,0 +1,24 @@
+import { JwtService } from '@nestjs/jwt';
+import { UsersService } from '../users/users.service';
+import { RegisterDto } from './dto/register.dto';
+import { LoginDto } from './dto/login.dto';
+export declare class AuthService {
+    private readonly usersService;
+    private readonly jwtService;
+    constructor(usersService: UsersService, jwtService: JwtService);
+    register(dto: RegisterDto): Promise<{
+        accessToken: string;
+        userId: number;
+        username: string;
+        role: string;
+        isPremium: boolean;
+    }>;
+    login(dto: LoginDto): Promise<{
+        accessToken: string;
+        userId: number;
+        username: string;
+        role: string;
+        isPremium: boolean;
+    }>;
+    private issueToken;
+}