feat: mail 이메일 인증 비동기 처리 추가

backend/src/main/java/com/edufocus/edufocus/EdufocusApplication.java

@@ -3,7 +3,9 @@ package com.edufocus.edufocus;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.data.jpa.repository.config.EnableJpaAuditing;
+import org.springframework.scheduling.annotation.EnableAsync;
 
+@EnableAsync
 @EnableJpaAuditing
 @SpringBootApplication
 public class EdufocusApplication {

backend/src/main/java/com/edufocus/edufocus/global/config/AsyncConfig.java

@@ -0,0 +1,32 @@
+package com.edufocus.edufocus.global.config;
+
+import org.springframework.aop.interceptor.AsyncUncaughtExceptionHandler;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.scheduling.annotation.AsyncConfigurer;
+import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
+import org.springframework.web.servlet.config.annotation.EnableWebMvc;
+
+import java.util.concurrent.Executor;
+
+@Configuration
+@EnableWebMvc
+public class AsyncConfig implements AsyncConfigurer {
+
+    @Override
+    @Bean(name = "mailExecutor")
+    public Executor getAsyncExecutor() {
+        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
+        executor.setCorePoolSize(5);
+        executor.setMaxPoolSize(10);
+        executor.setQueueCapacity(500);
+        executor.setThreadNamePrefix("MailExecutor-");
+        executor.initialize();
+        return executor;
+    }
+
+    @Override
+    public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
+        return AsyncConfigurer.super.getAsyncUncaughtExceptionHandler();
+    }
+}

backend/src/main/java/com/edufocus/edufocus/mail/service/MailServiceImpl.java

@@ -8,6 +8,7 @@ import lombok.ToString;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.mail.SimpleMailMessage;
 import org.springframework.mail.javamail.JavaMailSender;
+import org.springframework.scheduling.annotation.Async;
 import org.springframework.stereotype.Service;
 
 import java.util.Random;
@@ -27,6 +28,7 @@ public class MailServiceImpl implements MailService {
     private final RedisUtil redisUtil;
 
     @Override
+    @Async("mailExecutor")
     public void sendMail(String email) {
         String code = createRandomCode();