refactor: 增强代码注释以提升可读性和维护性

ruoyi-common/ruoyi-common-mail/src/main/java/org/dromara/common/mail/config/MailConfig.java

@@ -16,6 +16,12 @@ import org.springframework.context.annotation.Bean;
 @EnableConfigurationProperties(MailProperties.class)
 public class MailConfig {
 
+    /**
+     * 创建邮件账户配置。
+     *
+     * @param mailProperties 邮件配置属性
+     * @return 邮件账户
+     */
     @Bean
     @ConditionalOnProperty(value = "mail.enabled", havingValue = "true")
     public MailAccount mailAccount(MailProperties mailProperties) {