feat: expose account identity and eligibility boundary

src/main/java/com/lab/labtimesheet/feature/account/repository/InternProfileRepository.java

@@ -1,9 +1,14 @@
 package com.lab.labtimesheet.feature.account.repository;
 
+import java.time.LocalDate;
+
 import com.lab.labtimesheet.feature.account.model.InternshipStatus;
 import com.lab.labtimesheet.feature.account.model.entity.InternProfile;
 import org.springframework.data.jpa.repository.JpaRepository;
 
 public interface InternProfileRepository extends JpaRepository<InternProfile, Long> {
     boolean existsByUserIdAndInternshipStatus(Long userId, InternshipStatus status);
+
+    boolean existsByUserIdAndInternshipStatusAndInternshipStartDateLessThanEqualAndInternshipEndDateGreaterThanEqual(
+            Long userId, InternshipStatus status, LocalDate latestStartDate, LocalDate earliestEndDate);
 }

src/main/java/com/lab/labtimesheet/feature/account/service/AccountService.java

@@ -1,5 +1,7 @@
 package com.lab.labtimesheet.feature.account.service;
 
+import java.time.LocalDate;
+
 import com.lab.labtimesheet.feature.account.model.AccountStatus;
 import com.lab.labtimesheet.feature.account.model.GlobalRole;
 import com.lab.labtimesheet.feature.account.model.InternshipStatus;
@@ -42,6 +44,20 @@ public class AccountService {
                 .isPresent();
     }
 
+    @Transactional(readOnly = true)
+    public boolean isEligibleIntern(long userId, LocalDate workDate) {
+        if (workDate == null) {
+            throw new IllegalArgumentException("Work date is required");
+        }
+        return users.findById(userId)
+                .filter(user -> user.getGlobalRole() == GlobalRole.INTERN)
+                .filter(user -> user.getAccountStatus() == AccountStatus.ACTIVE)
+                .filter(user -> internProfiles
+                        .existsByUserIdAndInternshipStatusAndInternshipStartDateLessThanEqualAndInternshipEndDateGreaterThanEqual(
+                                user.getId(), InternshipStatus.ACTIVE, workDate, workDate))
+                .isPresent();
+    }
+
     @Transactional(readOnly = true)
     public AccountIdentity requireEligibleIntern(long userId) {
         if (!isEligibleIntern(userId)) {