refactor: UserService 생성

core/src/main/java/com/taskbuddy/core/domain/User.java

@@ -1,4 +1,14 @@
 package com.taskbuddy.core.domain;
 
-public record User(Long id) {
+import lombok.Getter;
+
+import java.time.LocalDateTime;
+
+@Getter
+public class User {
+    private Long id;
+    private boolean loggedIn;
+    private boolean reminderEnabled;
+    private LocalDateTime createdAt;
+    private LocalDateTime updatedAt;
 }

core/src/main/java/com/taskbuddy/core/service/UserService.java

@@ -0,0 +1,13 @@
+package com.taskbuddy.core.service;
+
+import com.taskbuddy.core.domain.User;
+import org.springframework.stereotype.Service;
+
+@Service
+public class UserService {
+
+    //임시 구현
+    public boolean isUserLoggedIn(User user) {
+        return user.isLoggedIn();
+    }
+}