feat: e92878a8에 누락된 코드 추가

src/main/kotlin/roomescape/member/implement/MemberValidator.kt

@@ -0,0 +1,22 @@
+package roomescape.member.implement
+
+import io.github.oshai.kotlinlogging.KLogger
+import io.github.oshai.kotlinlogging.KotlinLogging
+import org.springframework.stereotype.Component
+import roomescape.member.exception.MemberErrorCode
+import roomescape.member.exception.MemberException
+import roomescape.member.infrastructure.persistence.MemberRepository
+
+private val log: KLogger = KotlinLogging.logger {}
+
+@Component
+class MemberValidator(
+    private val memberRepository: MemberRepository
+) {
+    fun validateCanSignup(email: String) {
+        if (memberRepository.existsByEmail(email)) {
+            log.info { "[MemberValidator.validateCanSignup] 중복 이메일: email=$email" }
+            throw MemberException(MemberErrorCode.DUPLICATE_EMAIL)
+        }
+    }
+}